Earthing systems.TN, TT and IT, country by country.

Supply arrangements

Predominant

Not established

In use

Not recorded

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

No settled national code; IEC 60364 used on donor-funded work

RCD rule

Not confirmed; check local rules

Notes

Supply quality and installation practice vary widely; do not assume the supplier provides a protective earth.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TN-C, TT

Older networks often TN-C; newer work moving to TN-C-S, with TT in places.

Standard and RCDs

Standard

National adoption of IEC/HD 60364

RCD rule

30 mA RCD expected on socket circuits under HD 60364-based rules; enforcement varies.

Notes

Not confirmed. The ERE new-connections regulation (2024) makes the customer responsible for earth-fault protection and the building earthing system, with an earthing protocol for 20-50 kW connections, but names no TN/TT system. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT, TN (type not stated)

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived (Sonelgaz)

RCD rule

30 mA RCD on socket circuits.

Notes

Not confirmed against a utility document. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S). US territory.

Standard and RCDs

Standard

US NEC (American Samoa Administrative Code Title 12, §12.0225)

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Standard: verified. System and predominant: corroborated (ASAC service-entrance grounding per NEC + NEC 250.24 summary). RCD: unverified.

Corroborated

Supply arrangements

Predominant

TT

In use

TT

The building's general earth electrode must stay separate from the substation earths. This fits a TT arrangement, but FEDA does not name the scheme.

Standard and RCDs

Standard

Reglament d'instal·lacions elèctriques de baixa tensió (Govern d'Andorra, Oct 1988)

RCD rule

30 mA RCDs normally required.

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Iberian-derived practice: network neutral earthed, local electrode.

Standard and RCDs

Standard

Portuguese-derived rules (RTIEBT)

RCD rule

30 mA RCD expected.

Notes

Not confirmed. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S).

Standard and RCDs

Standard

NEC-influenced practice

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Earthing follows North American practice, but local adoption and enforcement were not confirmed from an official source. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

BS 7671 / NEC mixed practice

RCD rule

Not confirmed; check local rules

Notes

No authoritative statement of the domestic earthing system found. Check local rules.

Check local rules

Supply arrangements

Predominant

TT

In use

TT

Installations supplied from the public LV network must have their own protective earth (TT) per the AEA regulation and IRAM 2281. TN-S is used where a customer has its own MV/LV substation, but this was not confirmed from an opened source.

Standard and RCDs

Standard

AEA 90364 Reglamentación para la Ejecución de Instalaciones Eléctricas en Inmuebles (Part 7 Sección 770 Viviendas), applied by provincial regulators

RCD rule

RCD (interruptor diferencial) of 30 mA or less; where there is only a main board it must cover all circuits (ERSeP RG 10/2022, Cap. III 3.7)

Notes

The system, predominant arrangement and RCD rule come from the Córdoba regulator's (ERSeP) technical rule, which requires a TT protective earth per the AEA rules. Enforcement is provincial; the Buenos Aires area (ENRE) rules are not confirmed here.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TN-C, TT

Soviet-era housing commonly has a combined neutral and earth (TN-C) with no separate protective conductor; newer work moves to TN-C-S or TN-S.

Standard and RCDs

Standard

PUE (Rules for Electrical Installations) with national GOST/IEC 60364 adoptions

RCD rule

Not confirmed; check local rules

Notes

No authoritative source was found, so the systems shown are unconfirmed and no predominant arrangement is given. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

Aruba utility (Elmar) rules

RCD rule

Not confirmed; check local rules

Notes

No authoritative statement of the domestic earthing system found. Check local rules.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

Multiple earthed neutral (MEN): the supply neutral is earthed at many points on the network, and the installation's main earth is linked to the neutral at the main switchboard.

Standard and RCDs

Standard

AS/NZS 3000 Wiring Rules, MEN system

RCD rule

30 mA RCD on all final subcircuits in residential dwellings (AS/NZS 3000:2018)

Notes

The RCD rule was confirmed by WA Building and Energy and ERAC. MEN as the AS/NZS 3000 system was confirmed by an NZ government (NZQA) unit standard.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S, TT

Networks converted from TT to TN (Nullung) with very few exceptions remaining.

Standard and RCDs

Standard

OVE E 8101 / TAEV; Nullungsverordnung

RCD rule

30 mA RCD required in addition to Nullung on socket circuits up to 16 A.

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TN-C, TT

Soviet-era housing commonly has a combined neutral and earth (TN-C) with no separate protective conductor; newer work moves to TN-C-S or TN-S.

Standard and RCDs

Standard

PUE (Rules for Electrical Installations) with national GOST/IEC 60364 adoptions

RCD rule

Not confirmed; check local rules

Notes

No authoritative source was found, so the systems shown are unconfirmed and no predominant arrangement is given. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S).

Standard and RCDs

Standard

Bahamas practice; NEC-based

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Earthing follows North American practice, but local adoption and enforcement were not confirmed from an official source. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TT

In use

TT

TT is the only permitted arrangement: the supply neutral is solidly earthed and must not be earthed anywhere inside the premises. Every customer with its own service point provides copper-clad rod electrode(s), max 1.0 ohm.

Standard and RCDs

Standard

EWA Regulations for Electrical Installations (EDD)

RCD rule

Earth leakage protection mandatory: max 30 mA for all sockets and domestic apparatus, 300 mA for lighting, AC, water heaters and fixed cookers, 10 mA for underwater lighting, 500 mA (preferably 300 mA) for other equipment.

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

BNBC (2011 draft text) earths installations through ECCs to the building's own buried electrodes (target about 1 ohm). It does not name a TT/TN system or say whether the supply provides an earth.

Standard and RCDs

Standard

Bangladesh National Building Code (BNBC 2020), Part 8 Ch. 1

RCD rule

Not confirmed; no RCD rating in the BNBC text read.

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

BL&P requires customer installations to follow the most recent NEC, with the Chief Electrical Engineer (GEED) as authority having jurisdiction. It recommends single-point grounding referenced at the service entrance only, and the customer provides the service-entrance grounding (25 ohm target). This is the NEC bonded-neutral (TN-C-S equivalent) arrangement.

Standard and RCDs

Standard

NEC (NFPA 70), most recent edition, as applied by GEED; BL&P service and meter installation rules

RCD rule

GFCI per the adopted NEC 210.8 (not stated in the BL&P rules opened) (not confirmed)

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TN-C, TT, IT

TKP 339-2011 says installations up to 1 kV should normally use a TN system with a solidly earthed source. TT is allowed only where TN cannot give safe conditions, and then RCDs are compulsory. IT is used where supply must not be interrupted. A local energy-inspection notice says older housing was built with two-wire wiring. The residential code (TKP 45-4.04-149 / SN 4.04.01) was not opened, so the split between TN-C and TN-C-S in dwellings is not sourced.

Standard and RCDs

Standard

TKP 339-2011 (Belarus PUE equivalent; a 2021/2022 revision exists) / TKP 45-4.04-149 or SN 4.04.01-2019 for dwellings

RCD rule

TKP 339-2011 lists a 30 mA RCD as additional protection against direct contact and bans RCDs in four-wire TN-C circuits (4.3.5.5). A rule for dwelling socket circuits was not found in the text opened.

Notes

System: verified (TKP 339-2011 4.3.2.9-4.3.2.11, 4.3.5.5). Predominant: not sourced. RCD: partly verified (30 mA as additional protection; banned in TN-C). Check whether TKP 339-2022 has replaced the 2011 text.

Verified

Supply arrangements

Predominant

TT

In use

TN-C-S, TT, IT

Most domestic installations are TT, each with its own earth electrode. DSOs forbid using the network neutral as a protective conductor without explicit permission. TN-C is banned in domestic installations, and some networks are 3x230 V.

Standard and RCDs

Standard

AREI/RGIE

RCD rule

RCD at the origin of every domestic installation (300 mA), plus 30 mA RCDs for bathrooms and washing, drying and dishwashing machines.

Notes

No further notes.

Corroborated

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

The PUC (regulator) wireman procedures name the NEC and the BEL Service Installation Manual as the governing codes, and service-entrance drawings must show the ground rod and conductor. The NEC bonds the neutral at the service (250.24), which is equivalent to TN-C-S. Draft Electrical Design, Compliance and Inspection Regulations 2026 would adopt the NEC edition the PUC notifies.

Standard and RCDs

Standard

NEC (NFPA 70), edition not stated, with the BEL Service Installation Manual and PUC rules; draft 2026 regulations pending

RCD rule

GFCI per the adopted NEC 210.8; PUC plan rules require GFCI outlets to be marked on drawings (not confirmed)

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S). Mixed US and UK heritage.

Standard and RCDs

Standard

Bermuda wiring regulations; NEC-based practice

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Earthing follows North American practice, but local adoption and enforcement were not confirmed from an official source. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Not confirmed. The 2025 wiring rules require exposed parts and the neutral of mains and sub-mains to be connected to earth electrodes and defer details to BTS 272:2019, which was not opened.

Standard and RCDs

Standard

BEA/ERA Internal House Wiring Rules and Regulations 2025; BTS 272:2019

RCD rule

ELCB/RCD required at appropriate points (cl. 61); no mA rating given.

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TT

The CIEE Santa Cruz guide, based on NB 777, says TN-S and TT predominate in Santa Cruz and that distribution transformers have a solidly earthed star point. Small installations need an earth connection point at the meter panel. National predominance was not established.

Standard and RCDs

Standard

NB 777 (Norma Boliviana, instalaciones eléctricas interiores en baja tensión)

RCD rule

Not confirmed; check local rules

Notes

Single professional-body source (Colegio de Ingenieros Electricistas y Electrónicos de Santa Cruz, 2026), regional scope. No 30 mA RCD rule appears in its text, only in sample load schedules. Unverified. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Mixed legacy TN-C and TN-C-S, with TT in rural areas.

Standard and RCDs

Standard

Pravilnik o tehničkim normativima za električne instalacije niskog napona (Sl. list SFRJ 53/88) / EPBiH TP-10 / BAS HD 60364

RCD rule

30 mA RCD on socket circuits under HD 60364-based rules.

Notes

Not confirmed. A public-sector exam reading list (obs.ba) names the 1988 SFRJ regulation on LV installations and JP EPBiH technical recommendation TP-10 for LV connections, and one question states the customer installation protection must be TN-C/S. Single non-authoritative source. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

Electricity (Supply) Regulations 1988 require the supply undertaker's LV works to meet a TN-C-S (protective multiple earthing) system, with overall neutral resistance to earth not above 10 ohm. The consumer must also provide an earth electrode (20 ohm or less) near the point of supply. Inside the consumer installation the neutral must not be earthed or joined to any protective conductor.

Standard and RCDs

Standard

Electricity (Supply) Regulations 1988 (S.I. 52 of 1988), Second Schedule: installations to follow IEC standards and the IEE Wiring Regulations where possible.

RCD rule

RCD of not more than 30 mA on each final socket-outlet circuit (Second Schedule para. 2(a)); does not apply to premises under the Factories Act or the Mines, Quarries, Works and Machinery Act.

Notes

The regulation cites IEC and the IEE Wiring Regulations, not SANS 10142-1. It dates from 1988; check for later BPC or BOBS rules.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-S, TN-C-S, TT

Utility LV networks are 127/220 V with a multi-earthed neutral. CEMIG ND-5.1 requires the incoming neutral to be earthed at the service entrance (7.4.1.1), and the earthing conductor, neutral and protective conductor to be joined at the first box receiving the service (7.5.11). The PE is taken from that point, which is TN-C-S. NBR 5410 also recognises TN-S, TT and IT; TT is common where no PE is derived from the neutral.

Standard and RCDs

Standard

ABNT NBR 5410 (paywalled; read via summaries) plus distributor connection rules (e.g. CEMIG ND-5.1)

RCD rule

30 mA DR (RCD) on circuits serving locations with a shower or bath, outdoor sockets, indoor sockets that may feed outdoor equipment, and kitchens, laundries, service areas, garages and other wet or washed areas (NBR 5410 5.1.3.2.2)

Notes

An RCD cannot be used on TN-C unless the protected circuit is converted to TN-S. The predominant arrangement is confirmed only for the CEMIG area (Minas Gerais).

Corroborated

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

The BVI Government enforces the 2017 NEC (cited in its electrical inspection notice). The NEC bonds neutral to ground at the service (250.24), which is equivalent to TN-C-S.

Standard and RCDs

Standard

NEC (NFPA 70) 2017, enforced by the Government electrical inspection

RCD rule

GFCI per NEC 2017 210.8; the government notice also requires ground-fault protection of 30 mA or less at marinas and docks (NEC 555) (not confirmed)

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TT

Consumers normally provide their own earth electrode (TT).

Standard and RCDs

Standard

Electrical Installation Requirement 2011 (EIR), mandatory, based on the IET Wiring Regulations (BS 7671); EIR prevails where they conflict

RCD rule

30 mA RCD expected on socket circuits

Notes

Standard: corroborated (AFEO white paper, an ASEAN engineering-federation source). System, predominant and RCD: unverified. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S, TN-C

A Technical University of Gabrovo paper says all Bulgarian LV supply networks are TN-C. By law, new and renovated buildings are wired TN-C-S. In older buildings PE and N stay combined, so RCDs cannot be used in the panel.

Standard and RCDs

Standard

Naredba No 3 on electrical installations and power lines / BDS HD 60364

RCD rule

30 mA RCDs are the main type used against direct and indirect contact; Ordinance No. 3 bars RCDs whose operation depends on supply voltage in dwellings. A mandatory 30 mA socket rule was not confirmed.

Notes

System and predominant: unverified (a single university paper citing Ordinance No. 3; Ordinance text not opened). RCD: unverified. TT was dropped from the list: not mentioned in the source.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C, TT

The national technical standards recognise two LV earthing systems: TT (equipment earth electrodes independent of the supply earth) and TN (TN-S or TN-C). LV equipment at user sites follows IEC 60364 and, where connected directly to the supplier, must use the supplier's earthing system; one site may not mix systems. Exposed metal of LV equipment ≤300 V takes Class D earthing. Which system EDC normally supplies was not stated.

Standard and RCDs

Standard

Specific Requirements of Electric Power Technical Standards (MIME Prakas 701, 2007; updated 2017); IEC 60364 for user installations

RCD rule

Earth leakage breakers (0.5 s, or 1 s for Class B cases) allow higher earth resistance values; no general mA sensitivity or domestic RCD rule found

Notes

System: verified (Prakas 701 Art. 24(3)). Predominant: not sourced, null. RCD: verified only as earth-resistance alternative; no domestic 30 mA rule found. TN-C-S removed from list because the standard names TN-S and TN-C only.

Verified

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

As in the US: the neutral is earthed at the service and bonded to the bonding conductor system, which is the Canadian equivalent of TN-C-S.

Standard and RCDs

Standard

CSA C22.1 Canadian Electrical Code Part I (Section 10 grounding and bonding), adopted provincially

RCD rule

GFCI required for bathroom/washroom and exterior receptacles (CEC Rules 26-700 series) and other specified locations

Notes

Confirmed through Technical Safety BC. Provincial amendments vary.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT, IT

RTIEBT defines TN (TN-S, TN-C-S, TN-C), TT and IT schemes. Which one the utility supplies was not found.

Standard and RCDs

Standard

Regras Técnicas das Instalações Elétricas de Baixa Tensão (RTIEBT), approved by Portaria 34/2020 (BO I Série nº 92, 4 Aug 2020); mandatory for new installations from 1 Jan 2021.

RCD rule

RTIEBT 412.5 recognises RCDs of 30 mA or less as additional protection; the specific circuits where they are mandatory were not confirmed.

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

Caribbean Netherlands utility rules

RCD rule

Not confirmed; check local rules

Notes

No authoritative statement of the domestic earthing system found. Check local rules.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

The Cayman Islands Building Code Regulations adopt NFPA 70 (NEC) 2014 as amended. The NEC requires the neutral to be bonded to the grounding electrode and equipment grounding at the service (250.24), which is equivalent to TN-C-S.

Standard and RCDs

Standard

NFPA 70 National Electrical Code 2014 ed. as amended (Building Code Regulations, 2022 Revision, reg. 3(f))

RCD rule

GFCI per NEC 2014 210.8 as adopted (bathrooms, kitchens, garages, outdoors etc.) (not confirmed)

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TT

In use

TN-S, TT, IT

RIC N°05 6.7.1.1: consumer installations supplied directly from the public LV network use the TT scheme. For other consumer installations the choice is TN-S, TT or IT (6.7.1.2). TN-C and TN-C-S are allowed only where technically justified and TN-S is impossible (6.4.4/6.4.5). RIC N°06 requires the neutral to be earthed with a service earth of 20 ohms or less.

Standard and RCDs

Standard

SEC Pliegos Técnicos Normativos RIC N°01-N°19 (Resolución Exenta SEC 33.877 of 30/12/2020), notably RIC N°05, N°06 and N°10

RCD rule

All dwelling circuits must be protected by an RCD (protector diferencial), 30 mA for lighting and socket circuits, with no more than 3 circuits per RCD (RIC N°10 5.1.3.5, 5.1.3.7, 5.2 c)

Notes

Based on the SEC technical pliegos issued under REx 33.877, which replace NCh Elec 4/2003.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT

National design codes allow TT, TN-S or TN-C-S for civil buildings and say TN-C should be avoided. Local government guidance for new residential communities (e.g. Lishui, Zhejiang) specifies TN-C-S or TN-S, with the PE/PEN re-earthed where the supply enters the building. Rural practice (often said to be TT) was not confirmed.

Standard and RCDs

Standard

GB 55024-2022 (mandatory building electrical code); GB 50052-2009; GB 50054-2011; JGJ 242-2011 (residential electrical design); GB/T 16895 (IEC 60364)

RCD rule

RCD of 30 mA or less on circuits up to 32 A including general-use socket circuits (GB 55024-2022 cl. 4.6.5); Shenzhen guidance requires 30 mA on every socket and lighting circuit

Notes

System: verified (GB 50052-2009 explanatory notes to 7.0.1; GB 55024-2022 references TN and TT disconnection times). Predominant: not sourced nationally, set null; Lishui guidance (TN-C-S or TN-S for residential communities) is local only. RCD: verified (GB 55024 via English translation preview; Shenzhen guideline).

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

RETIE requires a main bonding jumper (puente de conexión equipotencial principal) in any board used as service equipment, sized per NTC 2050 250.28(D) (Art. 3.17.8 x), and in the main board (2.3.31.2.2 d). The neutral is bonded to earth at the service and kept separate downstream: the NEC-style equivalent of TN-C-S. Separate, independent earth systems in one building are prohibited (3.12.1 f).

Standard and RCDs

Standard

RETIE (Res. MME 40117 de 2024 as amended by Res. 40284 de 2026) with NTC 2050 segunda actualización (NEC-based)

RCD rule

Ground-fault (diferencial/GFCI) protection for receptacles within 1.8 m of showers and for electric showers without a shielded element (RETIE 3.17.15); 30 mA RCD on each EV charging point (3.17.7); NTC 2050 210.8 GFCI locations also apply but were not opened

Notes

Res. 40284 of 23 June 2026 amends RETIE in force from publication; transition rules apply.

Verified

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

The single-phase neutral must be multiple-earthed: at the source, at points along the line and on the consumer's premises (MEN). Overall neutral resistance to earth must not exceed 10 Ω.

Standard and RCDs

Standard

Electricity Supply Regulations 1992 and Electrical Wiring Regulations; AS/NZS 3000 framework (PRIF)

RCD rule

Not confirmed; check local rules

Notes

System and predominant: verified (regs 49, 52). Standard edition: corroborated only by PRIF grouping. RCD: unverified.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

The Código Eléctrico de Costa Rica (RTCR 458:2011, Decreto 36979-MEIC) adopts NFPA 70. NEC 2014 applies to new work with plans sealed after 7 Feb 2019. The NEC bonds the neutral at the service (250.24), which is equivalent to TN-C-S.

Standard and RCDs

Standard

Código Eléctrico de Costa Rica para la Seguridad de la Vida y de la Propiedad (RTCR 458:2011, Decreto 36979-MEIC, reformed by 43418-MEIC): NFPA 70 NEC 2014 for plans sealed after 7 Feb 2019

RCD rule

GFCI per NEC 2014 210.8; the verification checklist (Anexo C 8.8) checks GFCIs in wet areas (not confirmed)

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Both TN-C-S and TT are used depending on the distribution area.

Standard and RCDs

Standard

Tehnički propis za niskonaponske električne instalacije (NN 5/2010) / HRN HD 60364

RCD rule

30 mA RCD on socket circuits.

Notes

Standard verified: the Technical Regulation for LV Electrical Installations (NN 5/2010) applies HRN HD 60364 (incl. -4-41, -5-54). Systems, predominant and RCD: not confirmed; the HEP ODS grid code only says the operator tells the customer how the network neutral is earthed. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT, IT

Resolución 159/2014 (MINEM) makes NC IEC 60364 mandatory. Masses must be earthed according to the chosen earthing scheme (TN, TT or IT, summarised in Annex 4), with a total earth resistance of 2 ohms or less (Art. 43).

Standard and RCDs

Standard

NC IEC 60364 (mandatory under Reglamento de Seguridad Eléctrica, Res. MINEM 159/2014)

RCD rule

RCDs recognised as additional protection against direct contact (Art. 6 e); no specific domestic rating or location rule in the regulation

Notes

No specific RCD requirement was found in the regulation.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

Curacao utility (Aqualectra) rules

RCD rule

Not confirmed; check local rules

Notes

No authoritative statement of the domestic earthing system found. Check local rules.

Check local rules

Supply arrangements

Predominant

TT

In use

TN-C-S, TT

Installations have historically been TT. TN-C-S designs are allowed only with EAC approval (Directive TM/59/2007).

Standard and RCDs

Standard

BS 7671 (current edition) + Electricity Laws Cap. 170-171 and Electricity Regulations

RCD rule

30 mA RCDs are expected under BS 7671. Government guidance confirms it only for generator-fed circuits.

Notes

No further notes.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-S, TN-C-S, TN-C, TT

ČEZ Distribuce connection conditions require the main house feeder and meter branches to be TN-C, with meter boards TN-C on the supply side and TN-C or TN-C-S on the outgoing side. Other arrangements can be agreed for isolated small customers. In houses and flats the PEN is normally split in the meter or flat board, giving TN-C-S.

Standard and RCDs

Standard

ČSN 33 2000 (HD 60364) / ČSN 33 2130 / DSO connection conditions (Připojovací podmínky NN)

RCD rule

30 mA RCDs required by ČSN 33 2000-4-41 for additional protection; the exact socket-circuit clause was not opened.

Notes

System: verified (ČEZ Distribuce conditions 2.2, 2.3, 3.2). Predominant: corroborated (DSO TN-C supply with TN-C-S outgoing, plus CTU thesis stating TN-C-S is most common in Czech houses and flats). RCD: unverified. TT not mentioned in the DSO conditions and is kept only from earlier data.

Corroborated

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TT

In use

TN-C-S, TT

Most distribution transformers are operated as TT, and installations rely on an earth electrode plus mandatory RCDs. TN (nulling) installations need the grid company's approval and are typical for larger loads.

Standard and RCDs

Standard

Elinstallationsbekendtgoerelsen / DS/HD 60364

RCD rule

RCDs (max 30 mA) mandatory in all dwellings since 1 July 2008.

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

IEE (BS 7671) Wiring Regulations as applied by the Public Works Electrical Division; DBOS DNCP 2:2022 Code of Practice for Electrical Wiring (voluntary)

RCD rule

Not confirmed; check local rules

Notes

Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S).

Standard and RCDs

Standard

Reglamento para Instalaciones Electricas (NEC-based)

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Earthing follows North American practice, but local adoption and enforcement were not confirmed from an official source. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

The NEC-SB-IE residential chapter requires the TN-C-S neutral regime (sec. 8.3). The dwelling's main board has its own earth rod with an equipotential bond between the neutral and earth bars, while sub-boards keep neutral and earth separate (sec. 8.2). The service neutral is earthed (8.4).

Standard and RCDs

Standard

NEC-SB-IE Instalaciones Eléctricas Residenciales (Norma Ecuatoriana de la Construcción, MIDUVI 2018); not the US NEC

RCD rule

No GFCI/RCD requirement found in the NEC-SB-IE residential chapter (only overcurrent breakers); switches are prohibited in wet zones

Notes

Based on the MIDUVI NEC-SB-IE residential chapter.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Both TT and TN-C-S are used; the predominant system is not established.

Standard and RCDs

Standard

Egyptian Code for Electrical Installations

RCD rule

30 mA RCD expected on socket circuits.

Notes

Not confirmed. Check local rules.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

SIGET adopted the 2008 US NEC as the technical standard for user installations (Acuerdo 294-E-2011). AES El Salvador's electricians' manual requires every installation to have an earth electrode (5/8 in x 5 ft rod, 25 ohms or less), with the neutral solidly grounded at the main distribution panel. This is the NEC bonded-neutral arrangement, equivalent to TN-C-S.

Standard and RCDs

Standard

NEC 2008 (NFPA 70) adopted by SIGET Acuerdo 294-E-2011; SIGET Acuerdo 93-E-2008 for connections

RCD rule

GFCI per NEC 2008 210.8 as adopted by SIGET (not restated in the AES manual) (not confirmed)

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TT

Iberian-derived practice: network neutral earthed, local electrode.

Standard and RCDs

Standard

Spanish-derived rules (REBT)

RCD rule

30 mA RCD expected.

Notes

Not confirmed. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Consumers commonly provide their own earth electrode (TT); some urban utilities offer TN-C-S.

Standard and RCDs

Standard

IEC-based rules

RCD rule

RCD/ELCB protection (typically 30 mA) expected on socket circuits; enforcement varies.

Notes

Based on the British-derived technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TN-C, TT, IT

A Tallinn University of Technology thesis (2015) says parts of Tallinn's LV network still use the old 3x220 V unearthed IT system without a neutral, which Elektrilevi is replacing with TN-C in distribution. TN-S is recommended inside customer installations, and TN-C-S is seen as an interim step. Buildings from 1945-1990 commonly have TN-C. Elektrilevi's standard terms list 3x220 V among rated voltages.

Standard and RCDs

Standard

EVS-HD 60364

RCD rule

Not confirmed; the thesis notes RCDs cannot be used in TN-C.

Notes

System: unverified (single university thesis; Elektrilevi terms only confirm 3x220 V supplies still exist). Predominant: not sourced. RCD: unverified. Legacy IT 3x220 V added.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT

Supply authorities commonly provide an earth via the combined neutral (TN-C-S); TT is used on some rural and overhead supplies.

Standard and RCDs

Standard

SANS 10142-1 (with NRS 097 for embedded generation)

RCD rule

30 mA earth leakage protection on socket-outlet circuits in dwellings (SANS 10142-1).

Notes

SANS 10142-1 (sold, not freely published) is not confirmed here. No predominant arrangement is given because none is sourced. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Consumers commonly provide their own earth electrode (TT); some urban utilities offer TN-C-S.

Standard and RCDs

Standard

Ethiopian standards (IEC 60364-based)

RCD rule

RCD/ELCB protection (typically 30 mA) expected on socket circuits; enforcement varies.

Notes

Based on the British-derived technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

IEE Wiring Regulations as amended or replaced (now BS 7671), per Electricity Supply Regulations 1969 reg. 6

RCD rule

Not confirmed; check local rules

Notes

Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Predominant system not established.

Standard and RCDs

Standard

Old Danish heavy-current regulations (stærkstrømsreglementet), still in force as of 2020

RCD rule

Check local rules.

Notes

System, predominant and RCD unverified: no SEV earthing document was found. Check local rules.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

The Electricity Regulations 2019 make AS/NZS 3000:2018 the Wiring Rules for consumer installations. That standard uses the MEN (TN-C-S) system. The regulations require the neutral of LV three-phase four-wire systems to be earthed.

Standard and RCDs

Standard

AS/NZS 3000:2018, adopted by Electricity Regulations 2019 (Electricity Act 2017)

RCD rule

AS/NZS 3000:2018 applies: 30 mA RCD on all final subcircuits in residential installations

Notes

Standard: verified. System and predominant: corroborated (Fiji regulation adopting AS/NZS 3000:2018, plus NZ regulations/NZQA defining MEN as the AS/NZS system). RCD: corroborated (2018 edition rule confirmed by WA Building and Energy).

Corroborated

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

The DSO supply is TN-C (PEN); PE and N are separated at the main board, so the installation is TN-S from there.

Standard and RCDs

Standard

SFS 6000 (HD 60364)

RCD rule

RCDs on socket-outlet circuits (except refrigeration circuits) and on dwelling lighting circuits, per the City of Helsinki design guideline. The SFS 6000 30 mA clause is not confirmed here.

Notes

No further notes.

Verified

Supply arrangements

Predominant

TT

In use

TT, IT, TN (type not stated)

The public LV neutral is earthed at network level; homes have their own electrode (TT). TN and IT are used in private substations and industry.

Standard and RCDs

Standard

NF C 15-100

RCD rule

All dwelling circuits sit behind 30 mA RCDs: at least two RCDs, at most 8 circuits each, and type A (or F/B) for the cooking, washing machine and EV charging circuits.

Notes

No further notes.

Verified

Supply arrangements

Predominant

TT

In use

TT

Homes supplied from the EDF SEI public LV network have their own earth electrode, separate from the network neutral earth, which is a TT arrangement. The supply's branch breaker is typically a 500 mA differential type (NF C 14-100). TN and IT are possible in installations with their own MV/LV substation, but this was not confirmed from an opened source.

Standard and RCDs

Standard

NF C 15-100 (EDF SEI requires a Consuel attestation for connection); Arrêté du 3 août 2016 for new dwellings

RCD rule

30 mA RCDs on all final circuits of new dwellings (Arrêté du 3 août 2016 art. 2; NF C 15-100)

Notes

EDF SEI's guide confirms NF C 15-100 applies in this territory.

Corroborated

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT

Public network supplies are normally TT: the consumer provides an earth electrode and the supply neutral is earthed separately at the substation.

Standard and RCDs

Standard

NF C 15-100

RCD rule

30 mA RCDs required on all final circuits (NF C 15-100 practice)

Notes

French territory applying French installation rules. Not checked against a local official source for this territory. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Consumers commonly provide their own earth electrode (TT); some urban utilities offer TN-C-S.

Standard and RCDs

Standard

IEE-derived wiring rules

RCD rule

RCD/ELCB protection (typically 30 mA) expected on socket circuits; enforcement varies.

Notes

Based on the British-derived technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TN-C, TT

Soviet-era housing commonly has a combined neutral and earth (TN-C) with no separate protective conductor; newer work moves to TN-C-S or TN-S.

Standard and RCDs

Standard

PUE (Rules for Electrical Installations) with national GOST/IEC 60364 adoptions

RCD rule

Not confirmed; check local rules

Notes

No authoritative source was found, so the systems shown are unconfirmed and no predominant arrangement is given. Check local rules.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S, TT

The TN system is widespread (TN-C network, TN-S in buildings). Some operators hand over TT. Every new building needs a foundation earth (DIN 18014).

Standard and RCDs

Standard

DIN VDE 0100 (410:2018-10) / VDE-AR-N 4100 / TAB

RCD rule

30 mA RCD for AC sockets up to 32 A for general use, and for outdoor final circuits with portable equipment up to 32 A (DIN VDE 0100-410).

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Not confirmed. The earthing arrangement ECG/NEDCo supply was not found in an official source.

Standard and RCDs

Standard

Ghana Electrical Wiring Regulations 2011 (L.I. 2008), administered by the Energy Commission; covers indoor wiring only.

RCD rule

Not confirmed against the regulation text.

Notes

A 2023 university thesis applied an Energy Commission figure of under 50 ohm for consumer earth electrodes, but that was not confirmed in the regulation.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

UK practice is assumed, but no Gibraltar Electricity Authority document on earthing was found.

Standard and RCDs

Standard

BS 7671 (IEE/IET Wiring Regulations), deemed compliance under the Gibraltar Electricity Authority Act

RCD rule

30 mA RCD on socket circuits (BS 7671).

Notes

System and predominant are unverified. No predominant arrangement is given because none is sourced. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

The DSO (HEDNO/ΔΕΔΔΗΕ) decides the earthing system by network area, and the installation must match it. Both TT and TN exist. A university thesis says TN (neutralisation) is general nationwide except Athens, where TT remains. Foundation earthing is mandatory in new buildings.

Standard and RCDs

Standard

ΕΛΟΤ HD 384

RCD rule

RCDs of 30 mA or less are mandatory for all power circuits in new and existing installations (Ministerial Decision F.A 50/12081/642/2006; restated by HEDNO).

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT

Where the village network has five conductors, the installation must always connect to the network's continuous protective conductor (TN-S). Other areas are not described.

Standard and RCDs

Standard

Selvstyrets bekendtgørelse nr. 22 af 12. december 2019 / DS/HD 60364; Nukissiorfiit supplement to Fællesregulativet 2026

RCD rule

RCD protection on connection points up to 32 A as a rule. Nulling or double insulation are allowed alternatives.

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

BS 7671-based practice

RCD rule

Not confirmed; check local rules

Notes

No authoritative statement of the domestic earthing system found. Check local rules.

Check local rules

Supply arrangements

Predominant

TT

In use

TT

Homes supplied from the EDF SEI public LV network have their own earth electrode, separate from the network neutral earth, which is a TT arrangement. The supply's branch breaker is typically a 500 mA differential type (NF C 14-100). TN and IT are possible in installations with their own MV/LV substation, but this was not confirmed from an opened source.

Standard and RCDs

Standard

NF C 15-100 (EDF SEI requires a Consuel attestation for connection); Arrêté du 3 août 2016 for new dwellings

RCD rule

30 mA RCDs on all final circuits of new dwellings (Arrêté du 3 août 2016 art. 2; NF C 15-100)

Notes

EDF SEI's guide confirms NF C 15-100 applies in this territory.

Corroborated

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S). US territory.

Standard and RCDs

Standard

US NEC (NFPA 70), latest edition, adopted by Guam DPW building permit rules

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Standard: verified. System and predominant (TN-C-S by NEC service bonding): corroborated (Guam adoption + NEC 250.24 summary). RCD: unverified locally (GFCI per NEC).

Corroborated

Supply arrangements

Predominant

Not established

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S).

Standard and RCDs

Standard

NEC-based practice

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Earthing follows North American practice, but local adoption and enforcement were not confirmed from an official source. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Both PME and TT exist; the predominant system is not confirmed.

Standard and RCDs

Standard

BS 7671 (IET Wiring Regulations), applied under the Electricity (Guernsey) Law 2001

RCD rule

30 mA RCD on socket circuits (BS 7671).

Notes

System and predominant not confirmed: no Guernsey Electricity earthing document was found. RCD rule taken from BS 7671 411.3.3. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Iberian-derived practice: network neutral earthed, local electrode.

Standard and RCDs

Standard

Portuguese-derived rules

RCD rule

30 mA RCD expected.

Notes

Not confirmed. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

GPL rules; NEC-influenced practice

RCD rule

Not confirmed; check local rules

Notes

No authoritative statement of the domestic earthing system found. Check local rules. In 2008 the government announced it would build a Guyana code by adapting the US NEC, moving away from British-based standards (Stabroek News). Completion was not confirmed.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

No enforced national code

RCD rule

Not confirmed; check local rules

Notes

No authoritative statement of the domestic earthing system found. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S).

Standard and RCDs

Standard

NEC-based practice

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Earthing follows North American practice, but local adoption and enforcement were not confirmed from an official source. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TT

Many installations have their own earth electrode (TT). Where available, the installation earth may be bonded to the supply company's earthing terminal through a removable link (TN-S style).

Standard and RCDs

Standard

Code of Practice for the Electricity (Wiring) Regulations (EMSD)

RCD rule

RCD of 30 mA or less on socket-outlet circuits (COP Code 11J); also required for overhead-line supplies and New Territories village houses, and in bathrooms

Notes

RCD rules and the supply company earthing terminal were confirmed from EMSD and HK Electric documents. Which system predominates was not stated by either source. No predominant arrangement is given because none is sourced.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-S, TN-C-S, TN-C

A meter-cabinet system approval issued jointly by all Hungarian DSOs (ELMŰ, ÉMÁSZ, the three E.ON networks and MVM Démász) with MEE in 2021 gives the protective-conductor system as TN-C on the unmetered side and TN-S on the metered side. MEE material citing MSZ 447:2019 says the PEN must be split at the connection point in the main connection board, or after it if that is not feasible. TT was not mentioned in any source opened.

Standard and RCDs

Standard

MSZ HD 60364 / MSZ 447:2019 (connection to the LV network) / 40/2017 (XII.4) NGM rendelet

RCD rule

MEE network-connection checklist: an RCD rated 30 mA or less must be present in the metered distribution board.

Notes

System: verified (joint DSO system approval). Predominant: corroborated (DSO approval TN-C unmetered / TN-S metered, plus MEE FAQ on MSZ 447:2019 PEN split at the connection point). RCD: unverified (MEE checklist only). The DSO approval was read from a copy on a distributor's website (mentavill.hu).

Corroborated

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S, TT

Urban distribution is generally TN-C (3N~400/230 V), and all construction in recent decades uses it, so installations are TN-C-S. TT remains in the oldest districts (e.g. older Reykjavík and Akranes) and needs a customer-owned earth electrode.

Standard and RCDs

Standard

Reglugerð um raforkuvirki nr. 678/2009 (art. 11) with the ÍST HD 60364 series

RCD rule

RCD of 30 mA or less on installations in dwellings, schools, nurseries, hotels and public buildings (Reglugerð 678/2009 art. 11.2).

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT

CEA Regulations 2023 require the supplier to provide an earthed terminal at the point of supply (reg. 18) and the LV neutral to be earthed at the consumer's premises and at further points along the network (reg. 43(ii)), which is a TN-C-S (PME-type) arrangement; installations above 250 V must add their own electrode linked to the supplier's terminal. IS 3043 describes TN-S, TN-C-S and TT, and states single-phase TT is not present in India (TT is for three-phase industrial supplies). Many homes also have a local earth pit; the share of each arrangement was not sourced.

Standard and RCDs

Standard

CEA (Measures relating to Safety and Electric Supply) Regulations 2023; IS 732:2019 (wiring); IS 3043 (earthing)

RCD rule

RCD required on installations (reg. 44); max 30 mA for domestic installations.

Notes

Based on the 1987 edition of IS 3043; a 2018 revision exists.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S, TT, IT

PUIL 2011 calls TN-C-S the most common system in Indonesia and the generally applicable one. TT is used mainly for installations with a lot of electronic or communication equipment. IT is also said to be common. TN-C is forbidden. TN-S is uncommon because PLN supplies only four conductors (three lines and a neutral) on three-phase connections.

Standard and RCDs

Standard

PUIL 2011 (SNI 0225:2011), based on IEC 60364

RCD rule

Additional protection by an RCD (GPAS) of 30 mA or less for socket-outlets up to 20 A used by ordinary persons (PUIL 2011 411.3.3). The RCD may sit at the main board or at each outlet. RCDs may not be used in TN-C (411.4.5).

Notes

IT is also permitted. One academic paper says TT is common at consumers, but the code's explanatory notes give TN-C-S.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-S, TN-C-S, TT, IT

Topic 13 sets TN as the general system for all buildings, type TN-C-S (or TN-S per its Appendix 1). TT, IT or safe extra-low voltage only where justified and notified in advance.

Standard and RCDs

Standard

Iran National Building Regulations, Topic 13 (Mabhas 13)

RCD rule

30 mA RCDs permitted for indirect-contact protection in homes and offices; not usable on circuits without a PE conductor. A general mandate was not found in the text read.

Notes

Based on the 1382/1392 edition; a later edition may differ.

Verified

Supply arrangements

Predominant

TT

In use

TN-S, TN-C-S, TN-C, TT

The Iraqi codes state TT is the common system and the one used by distribution in Iraq: the Ministry of Electricity earths the transformer neutral and consumers earth exposed parts to their own electrode (max 10 ohm in the installations code; 1 ohm cited for TT touch protection in the earthing code). TN-S, TN-C-S and TN-C are described; IT is not used on public supplies.

Standard and RCDs

Standard

Iraqi Electrical Installations Code M.B.A 1/402 (2015); Earthing and Lightning Protection Code M.B.A 301/402; Conditions for Electricity Supply (1994)

RCD rule

30 mA RCD required on outdoor sockets; a general residential mA rule was not found in the parts read. Since 1995 every socket must have an earth wire for earth-leakage protection.

Notes

Based on a scanned copy in which some figures are illegible; check the official text.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S, TT

ESB Networks lets the customer earth be connected to the network neutral (the 'neutralising link'), with a local earth electrode as well, so the result is TN-C-S with an extra electrode.

Standard and RCDs

Standard

I.S. 10101 National Rules for Electrical Installations (NSAI/ETCI)

RCD rule

30 mA RCD protection on final circuits in dwellings, including lighting circuits.

Notes

Safe Electric registered contractors must follow I.S. 10101.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Both PME and TT are likely, as in UK practice, but no Manx Utilities source confirms which is used.

Standard and RCDs

Standard

BS 7671

RCD rule

30 mA RCD on socket circuits (BS 7671).

Notes

A 2025 Isle of Man government consultation lists BS 7671 as relevant UK guidance but warns that Manx law may differ. No predominant arrangement is given because none is sourced. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Israeli regulations recognise 'ipus' (TN-C-S) and 'protective earthing' (TT), as shown by the 2025 gazette amendment that replaced the TN-C-S and TT labels with these terms. Which is predominant on IEC supplies was not sourced.

Standard and RCDs

Standard

Electricity Law 1954; Electricity Regulations (Earthing and Protective Measures against Electric Shock up to 1000 V), 1991

RCD rule

30 mA RCD on final circuits feeding sockets up to 32 A, 100 mA above 32 A, 300 mA on lines to boards (agricultural-premises regulation, 2025). Safety institute states 30 mA RCDs are required in every residential panel.

Notes

No further notes.

Verified

Supply arrangements

Predominant

TT

In use

TN-S, TT

Users supplied directly at LV from the distributor are TT with their own earth electrode. TN-S is used where the customer owns the MV/LV substation.

Standard and RCDs

Standard

CEI 64-8

RCD rule

RCDs are the practical means of disconnection in TT; 30 mA on sockets up to 32 A.

Notes

No further notes.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

Residential electrical provisions in the 2023 Jamaica Small Building/Residential Code are based on the 2017 NEC, so the NEC service bonding of neutral to ground (250.24) applies, equivalent to TN-C-S. Installations need a Government Electrical Inspector certificate before connection.

Standard and RCDs

Standard

2023 Jamaica Small Building/Residential Code (BSJ/ICC), electrical provisions based on NEC 2017; Government Electrical Inspectorate certification

RCD rule

GFCI per NEC 2017 210.8 as adopted in the residential code (not confirmed)

Notes

The OUR Supply Code draft only requires effective earthing and prohibits pipes as earths.

Verified

Supply arrangements

Predominant

TT

In use

TN-S, TT

The utility earths the low-voltage side of the distribution transformer (Class B earthing), kept as a separate electrode. Customer equipment is earthed to its own local electrode (Class D for 300 V or less), so homes are TT. TN systems are found in some large buildings and are becoming more common there.

Standard and RCDs

Standard

Technical Standards for Electrical Equipment (METI ministerial ordinance) and its Interpretation; Internal Wiring Regulations JEAC 8001 (内線規程)

RCD rule

Earth leakage breaker required on circuits feeding metal-cased LV equipment over 60 V (Interpretation of the Technical Standards, Art. 36), with stated exceptions; a main ELB is usual in homes

Notes

System: corroborated (IEIEJ journal paper contrasts Japan's TT with Western TN; TEPCO and Panasonic describe the separate transformer Class B earth). Predominant: corroborated (same sources). RCD: corroborated (JEMA quotes Interpretation Art. 36; the METI text itself was not readable). The rated sensitivity (15/30 mA) for homes was not confirmed.

Corroborated

Supply arrangements

Predominant

TN-C-S

In use

TN-S, TN-C-S, TT

New and replacement services are PME. Older SNE (TN-S) services exist. RCD plus own electrode is used where PME is not allowed.

Standard and RCDs

Standard

BS 7671 / Jersey Electricity requirements

RCD rule

30 mA RCD on socket circuits (BS 7671).

Notes

The standard is backed by the Building Bye-laws Part 12 guidance, which treats BS 7671 as a way to comply. The RCD rule comes from BS 7671 411.3.3 (see the IET source).

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Not confirmed.

Standard and RCDs

Standard

Jordan National Electrical Code

RCD rule

30 mA RCD expected.

Notes

No authoritative source was found. Check local rules.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-S, TN-C-S, TN-C, TT, IT

Kazakhstan's PUE (Minenergo order No. 230 of 20 March 2015) says installations up to 1 kV in residential, public and industrial buildings should be fed from a solidly earthed source with automatic disconnection, i.e. TN. A separate earth electrode (TT) is allowed only where TN cannot give safe conditions, and then with an RCD. An isolated neutral (IT) is used where interruption on a first fault is unacceptable. Residential, public and administrative buildings must be fed from a 380/220 V network with TN-S or TN-C-S (para. 2073). Older flats with two-wire wiring exist, but no share is sourced.

Standard and RCDs

Standard

PUE of the Republic of Kazakhstan (Minenergo order No. 230, 20 March 2015, reg. No. 10851)

RCD rule

PUE RK para. 2138: RCDs of 30 mA or less should be used on socket circuits. Para. 2131 makes an RCD compulsory where the 0.4 s disconnection time cannot be met and there is no equipotential bonding. A fire-protection RCD up to 300 mA is recommended at the flat or house intake (para. 2143). Para. 250: 30 mA RCDs for outdoor sockets. RCDs are not allowed in four-wire three-phase (TN-C) circuits (para. 183).

Notes

System: verified (PUE RK paras. 159-161, 183). Predominant: verified as the arrangement required for residential buildings (para. 2073: TN-S or TN-C-S); share of legacy TN-C not sourced. RCD: verified (paras. 2131, 2138, 2143). Text read on zakon.uchet.kz because adilet.zan.kz needs JavaScript.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

KS 662-3 (2026 draft) describes TN-S, TN-C-S (PME), TT and IT and says the earthing system depends on the application. It forbids a consumer from combining neutral and protective functions in one conductor. It does not say which arrangement Kenya Power supplies.

Standard and RCDs

Standard

KS 662 Requirements for electrical installations (KEBS). The third edition is a public review draft (March 2026) replacing KS 662:2001.

RCD rule

Draft KS 662-4:2026 requires 30 mA RCD additional protection for socket-outlets up to 32 A, mobile equipment up to 32 A used outdoors, and final circuits supplying luminaires in domestic premises.

Notes

Not yet confirmed against the EPRA draft Electricity Supply and Installation Work Regulations 2024.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

SAA Wiring Rules (AS 3000 lineage), Electricity Regulations 1981 under the Public Utilities Ordinance

RCD rule

Not confirmed; check local rules

Notes

Standard: verified. System, predominant, RCD: unverified (regulations silent on earthing). No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Mixed legacy practice.

Standard and RCDs

Standard

IEC 60364-based national rules

RCD rule

30 mA RCD expected.

Notes

No authoritative source was found, so the systems shown are unconfirmed and no predominant arrangement is given. Check local rules.

Check local rules

Supply arrangements

Predominant

TT

In use

TT

TT is the specified supply arrangement: solidly earthed neutral, never earthed inside the consumer's premises. Each consumer drives a 16 mm copper-clad rod at least 3 m deep beside the intake; overall earth resistance must be under 2 ohms.

Standard and RCDs

Standard

MEW R-1 Regulations for Electrical Installations (6th edition, 2013)

RCD rule

ELCBs mandatory on every installation: 30 mA for all sockets and domestic apparatus, 300 mA for lighting, 300 mA (max 500 mA) for AC plant, lifts and pumps, 10 mA for underwater lighting.

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TN-C, TT

Soviet-era housing commonly has a combined neutral and earth (TN-C) with no separate protective conductor; newer work moves to TN-C-S or TN-S.

Standard and RCDs

Standard

PUE (Rules for Electrical Installations) with national GOST/IEC 60364 adoptions

RCD rule

Not confirmed; check local rules

Notes

No authoritative source was found, so the systems shown are unconfirmed and no predominant arrangement is given. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

Lao Electric Power Technical Standards (mandatory); IEC based

RCD rule

Not confirmed; check local rules

Notes

Standard: corroborated (AFEO). System, predominant, RCD: unverified. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-S, TN-C-S, TN-C, TT

The Latvenergo / Latvian Electrotechnical Committee standard LEK 048:2023 requires public, residential and production buildings to be fed from a solidly earthed source, i.e. a TN system. TT is allowed only where TN cannot meet the safety requirements, and then RCDs are compulsory. Where a TN-C supply changes to TN-C-S before a building's service entrance, the PEN busbar must be re-earthed (max 30 ohm).

Standard and RCDs

Standard

LBN 261-15 (Cabinet regulation No. 294, 2015, amended 2025) / LEK 048:2023 / LVS HD 60364

RCD rule

LBN 261-15 (as amended by Cabinet regulation No. 355 of 17 June 2025) cl. 28.1: RCDs of 30 mA or less on general-use sockets up to 32 A, outdoor sockets up to 32 A and household lighting circuits. Cl. 28.2: 300-500 mA protection at the main board of individual dwellings. LEK 048: RCDs not for use in TN-C.

Notes

System: verified (LEK 048:2023 2.23, 2.25). Predominant: corroborated (LEK 048 TN requirement with TN-C supply changing to TN-C-S at the building, plus Riga Technical University guidance). RCD: verified (LBN 261-15 cl. 28 as amended 2025). TT re-added: LEK 048 permits it as an exception.

Corroborated

Supply arrangements

Predominant

Not established

In use

TT

Not confirmed.

Standard and RCDs

Standard

IEC-based rules

RCD rule

30 mA RCD expected.

Notes

No authoritative source was found. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT

Supply authorities commonly provide an earth via the combined neutral (TN-C-S); TT is used on some rural and overhead supplies.

Standard and RCDs

Standard

SANS 10142-1 (with NRS 097 for embedded generation)

RCD rule

30 mA earth leakage protection on socket-outlet circuits in dwellings (SANS 10142-1).

Notes

SANS 10142-1 (sold, not freely published) is not confirmed here. No predominant arrangement is given because none is sourced. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Consumers commonly provide their own earth electrode (TT); some urban utilities offer TN-C-S.

Standard and RCDs

Standard

US/IEE mixed practice

RCD rule

RCD/ELCB protection (typically 30 mA) expected on socket circuits; enforcement varies.

Notes

Based on the British-derived technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Both TT and TN-C-S are used; the predominant system is not established.

Standard and RCDs

Standard

IEC-based national rules

RCD rule

30 mA RCD expected on socket circuits.

Notes

Not confirmed. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S

Swiss TN practice is likely, but no Liechtenstein DSO document was found.

Standard and RCDs

Standard

NIV (LGBl. 2007 Nr. 220), which recognises the Swiss NIN

RCD rule

30 mA RCD on all socket circuits up to 32 A (NIV Art. 4(3)). In justified cases 100 mA or other measures are allowed.

Notes

No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TN-C, TT, IT

The General Rules for Electrical Installations (EIIBT, Energy Minister order No. 1-22 of 2012) recognise TN (TN-S, TN-C, TN-C-S), TT and IT systems up to 1000 V. TT is described for hazardous rooms and outdoor sites where safe touch voltage must be ensured, and IT for sites with very high safety needs or where supply must not be cut after a first earth fault. Once the PEN is split, N and PE must not be rejoined. The text opened does not say which system is normal for homes.

Standard and RCDs

Standard

Elektros įrenginių įrengimo bendrosios taisyklės (Energy Minister order No. 1-22, 3 Feb 2012) / LST HD 60364

RCD rule

EIIBT clause 196: residual-current protection for individual installations must trip at 30 mA or less; 10 mA for portable equipment (clause 246). No socket- or dwelling-specific rule was found in the text opened.

Notes

System: verified (EIIBT clauses 195-198). Predominant: not sourced. RCD: verified as a general 30 mA limit; socket-circuit rule not confirmed.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S, TT

The DSO technical connection conditions (TAB-BT) require the PEN to be split into PE and N in the meter cabinet for TN installations, and a DIN 18014 foundation earth in every new building. TT is not described.

Standard and RCDs

Standard

TAB-BT 2021.1 (ILR-approved) / DIN VDE 0100

RCD rule

Check local rules: TAB-BT refers to DIN VDE 0100-410, but the RCD clause was not confirmed.

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TT

CEM supplies 230/400 V and building risers carry 3P + N + PE with an earth electrode for protection by automatic disconnection. The earthing system type was not stated.

Standard and RCDs

Standard

CEM NCEM C14-100 for building supply; IEC/CENELEC and Portuguese LV installation rules referenced where Macau rules are silent

RCD rule

Not confirmed; check local rules

Notes

All facts unverified apart from the CEM supply details. The name of the Macau LV installation regulation was not confirmed.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Consumers commonly provide their own earth electrode (TT); some urban utilities offer TN-C-S.

Standard and RCDs

Standard

ESCOM / MBS wiring rules

RCD rule

RCD/ELCB protection (typically 30 mA) expected on socket circuits; enforcement varies.

Notes

Based on the British-derived technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TT

In use

TN-S, TN-C-S, TT

Each installation must have its own earth electrode system, and the supply neutral may only be earthed at one point without Commission approval; this gives a TT arrangement for typical homes.

Standard and RCDs

Standard

Electricity Regulations 1994; MS IEC 60364

RCD rule

30 mA RCD for final circuits where hand-held appliances are used, 10 mA in wet or public-entertainment locations, 100 mA elsewhere (Electricity Regulations 1994, reg 36)

Notes

Regulations opened. They do not use the term TT, but the earthing rules describe it.

Verified

Supply arrangements

Predominant

Not established

In use

TN-S, TT

Not confirmed. A 2013 MEA draft allowed TN, TT or IT per IEC 60364; it was never enacted per ESCAP.

Standard and RCDs

Standard

IEC 60364 based; URA (formerly MEA) installation standards

RCD rule

Not confirmed. The 2013 draft proposed residual current protection on all installations, 30 mA for households and up to 100 mA for central AC.

Notes

Only a draft regulation was found. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TT

In use

TT, TN (type not stated)

Every installation needs its own earth electrode (16 mm² copper earthing conductor). It may also be connected to the DSO substation earthing point where technically feasible. Water pipes are not acceptable as an earth.

Standard and RCDs

Standard

Electricity Installations Regulations (S.L. 545.09, L.N. 225 of 2010 as amended); BS 7671

RCD rule

A 30 mA RCD immediately after the overvoltage device at the intake (Electricity Installations Regulations reg. 20(5)). In multi-customer buildings a 100 mA device at the meter is allowed, followed by 30 mA at each intake.

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S). Compact of Free Association state using US-style supply.

Standard and RCDs

Standard

US NEC-based practice

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Earthing follows North American practice, but local adoption and enforcement were not confirmed from an official source. Check local rules. No predominant arrangement is given because none is sourced. Standard: corroborated only by PRIF grouping.

Check local rules

Supply arrangements

Predominant

TT

In use

TT

Homes supplied from the EDF SEI public LV network have their own earth electrode, separate from the network neutral earth, which is a TT arrangement. The supply's branch breaker is typically a 500 mA differential type (NF C 14-100). TN and IT are possible in installations with their own MV/LV substation, but this was not confirmed from an opened source.

Standard and RCDs

Standard

NF C 15-100 (EDF SEI requires a Consuel attestation for connection); Arrêté du 3 août 2016 for new dwellings

RCD rule

30 mA RCDs on all final circuits of new dwellings (Arrêté du 3 août 2016 art. 2; NF C 15-100)

Notes

EDF SEI's guide confirms NF C 15-100 applies in this territory.

Corroborated

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Consumers commonly provide their own earth electrode (TT); some urban utilities offer TN-C-S.

Standard and RCDs

Standard

BS 7671-based rules (CEB)

RCD rule

RCD mandatory for new connections (CEB); CEB says RCD protection is required by law. Rating not stated.

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

TT

In use

TT

French overseas department: public LV distribution follows French practice, with the network neutral earthed at the substation and a separate installation earth electrode (TT).

Standard and RCDs

Standard

NF C 15-100

RCD rule

30 mA RCDs required at least on socket-outlet circuits (NF C 15-100).

Notes

The RCD rule is corroborated for socket-outlets; the full NF C 15-100 dwelling rules are not confirmed here.

Corroborated

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

NOM-001-SEDE-2012 250-24 requires the grounding electrode conductor to be connected to the grounded (neutral) service conductor at the service, and 250-24(b)/250-28 require a main bonding jumper joining the equipment grounding conductors to the neutral there. Neutral and ground stay separate downstream: the NEC-style equivalent of TN-C-S.

Standard and RCDs

Standard

NOM-001-SEDE-2012 Instalaciones Eléctricas (utilización), DOF 29 Nov 2012 (NEC-derived)

RCD rule

GFCI (interruptor de circuito por falla a tierra) on 120 V 15/20 A dwelling receptacles in bathrooms, garages, outdoors, crawl spaces, unfinished basements, kitchen countertops, within 1.80 m of other sinks and boathouses (210-8(a)); low-cost dwellings up to 60 m2 may protect the circuit at its origin instead

Notes

A revision of the NOM has been in preparation; check the DOF for a newer edition.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S). Compact of Free Association state using US-style supply.

Standard and RCDs

Standard

US NEC-based practice

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Earthing follows North American practice, but local adoption and enforcement were not confirmed from an official source. Check local rules. No predominant arrangement is given because none is sourced. Standard: corroborated only by PRIF grouping.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-S, TN-C-S, TN-C, TT, IT

NCM G.01.02:2025 requires TN-S or TN-C-S earthing in building installations, with repeat earthing of PE and PEN recommended. Working neutral and protective conductor must not share a terminal. The code still covers legacy TN-C supplies (an appliance PE connected to the PEN ahead of the RCD), and TT and IT are also referenced.

Standard and RCDs

Standard

NCM G.01.02:2025 (MIDR order No. 64 of 7 May 2025) / ANRE Normativ for electrical installations (Moldovan PUE equivalent)

RCD rule

NCM G.01.02:2025 Annex F: RCDs compulsory on socket circuits in rooms of residential buildings (F.3) and recommended for flat socket circuits (F.4), rated 30 mA or less (F.17). In major renovation of blocks of flats a 30 mA RCD goes in the floor or flat panel (18.24).

Notes

System and predominant: verified as required by NCM G.01.02:2025 cl. 18.4 (TN-S or TN-C-S); TN-C-S chosen as predominant because the code mandates TN-S/TN-C-S and still provides for PEN supplies. The share of legacy TN-C flats is not sourced. RCD: verified.

Verified

Supply arrangements

Predominant

Not established

In use

TT

Follows French practice.

Standard and RCDs

Standard

NF C 15-100 (required by SMEG)

RCD rule

30 mA RCDs on final circuits (NF C 15-100).

Notes

The earthing system and predominant are not stated by SMEG; TT is likely, as in France, but unconfirmed. RCD rule assumed from NF C 15-100. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TN-C, TT

Older apartment blocks follow Soviet-style TN-C; newer buildings increasingly use TN-C-S.

Standard and RCDs

Standard

National rules derived from PUE, with IEC 60364 influence

RCD rule

Not confirmed; check local rules

Notes

No authoritative source was found, so the systems shown are unconfirmed and no predominant arrangement is given. Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Mixed practice.

Standard and RCDs

Standard

MEST HD 60364

RCD rule

30 mA RCD on socket circuits.

Notes

Not confirmed. The 0.4 kV network neutral is directly earthed (UNDP / Elektroinstitut Milan Vidmar study, 2012, citing technical recommendation TP-6). A municipal design project in Kolasin uses TN-C-S for indirect-contact protection and cites MEST HD 60364-4-41. Single non-authoritative sources only. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

IEE (BS 7671) Wiring Regulations and Montserrat Building Code (Electrical Installations Act schedules)

RCD rule

Not confirmed; check local rules

Notes

Check local rules.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT, TN (type not stated)

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100 / NM 06.1.100

RCD rule

30 mA RCD on socket circuits.

Notes

Not confirmed against a utility document. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TT, TN (type not stated)

The LV distribution network safety regulation requires networks to run with the neutral directly earthed at substations and along the lines, global neutral earth resistance 10 ohm or less. It also allows a 'terra pelo neutro' system, in which exposed metalwork of installations is earthed through the network neutral and consumer electrodes may serve as network earths (global resistance 5 ohm or less). Which arrangement predominates was not found.

Standard and RCDs

Standard

Regulamento de Segurança de Redes de Distribuição de Energia Eléctrica em Baixa Tensão (Decreto 67/2011) for networks; separate LV installation safety regulation for consumer installations.

RCD rule

Not confirmed; installation rules are in a separate Regulamento de Segurança de Instalações Eléctricas em BT, which was not opened.

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

Electrical Regulations 1985 (being amended); Myanmar National Building Code electrical part; IEC/BS practice

RCD rule

Not confirmed; check local rules

Notes

Standard: partly corroborated (AFEO lists no mandatory standard; mentions 1985 regulations). System, predominant, RCD: unverified.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT

Not confirmed. No Namibian source opened states the earthing arrangement.

Standard and RCDs

Standard

SABS 0142 / SANS 10142-1 (the Model Electricity Supply Regulations 1996 define the Wiring Regulations as the SABS 0142 code of practice).

RCD rule

Not confirmed.

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

AS/NZS 3000:2007 (used by Nauru Utilities Authority)

RCD rule

Not confirmed; check local rules

Notes

Standard: corroborated (ADB-funded report). System, predominant, RCD: unverified. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Not confirmed. The Electricity Rules require appliance earthing and earthed three-pin sockets but name no system.

Standard and RCDs

Standard

Electricity Rules 2050 (1993); Nepal National Building Code NBC 207 (electrical)

RCD rule

Not confirmed; no earth-leakage device rule in the Electricity Rules.

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Operators offer an earthing facility (TN) where one is available, and it is mandatory for new connections above 3x80A. Where none is offered, the installation is TT. The TN/TT split for homes is not confirmed.

Standard and RCDs

Standard

NEN 1010 (required by the Besluit bouwwerken leefomgeving)

RCD rule

30 mA RCDs on sockets up to 32 A for general use, on outdoor portable equipment up to 32 A, and on lighting final circuits in dwellings (NEN 1010:2020).

Notes

No further notes.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-S, TN-C-S, TT

Public network supplies are normally TT: the consumer provides an earth electrode and the supply neutral is earthed separately at the substation.

Standard and RCDs

Standard

NF C 15-100 (version applicable in New Caledonia; mandatory for workplaces by Arrêté 2007-2027/GNC; required by ENERCAL and EEC supply conditions)

RCD rule

ENERCAL guide: 30 mA differential breaker at the start of each circuit, with a good earth electrode (utility advice)

Notes

Standard: verified. RCD: verified as utility advice (ENERCAL). System: unverified (each dwelling's own earth electrode is required, consistent with TT, but no source names the scheme). Predominant: null.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

Multiple earthed neutral (MEN), as in Australia: the neutral is bonded to the installation earth at the main switchboard.

Standard and RCDs

Standard

AS/NZS 3000 Wiring Rules (Part 2 compulsory for small domestic installations), cited by Electricity (Safety) Regulations 2010

RCD rule

RCD rules are those of AS/NZS 3000 (reg 24 sets RCD performance; reg 89 RCD for hand-held appliances in damp/outdoor use). The domestic RCD scope in AS/NZS 3000 was not opened directly

Notes

System and predominant: verified (regs 4 and 27: standard LV installations must be connected to a MEN system with a MEN switchboard). RCD: partly verified.

Verified

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

The Código de Instalaciones Eléctricas de Nicaragua (CIEN) defines the main bonding jumper as the connection between the grounded circuit conductor and the equipment grounding conductor at the service (Art. 110). This is the NEC-style bonded neutral, equivalent to TN-C-S.

Standard and RCDs

Standard

Código de Instalaciones Eléctricas de Nicaragua (CIEN), enforced by INE; NEC-patterned

RCD rule

GFCI on 120 V 15/20 A dwelling receptacles in bathrooms, garages, outdoors at grade, basements, and countertops within 1.80 m of sinks (CIEN 210-8(a))

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TT

Follows French-derived practice: earthed network neutral, local electrode at the installation.

Standard and RCDs

Standard

NF C 15-100-derived national rules

RCD rule

30 mA RCD expected on socket circuits; enforcement varies.

Notes

Based on the French/Belgian technical heritage; not confirmed nationally. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TT

In use

TN-C-S, TT

NESIS (2014 NERC text) requires the neutral of LV and MV distribution systems to be earthed at multiple points: at the point of supply, every fifth pole and the terminal poles, with not more than 2 ohm to earth. It states that the consumer's earth must not be connected to the neutral conductor, which is a TT arrangement. Where the supply undertaking does provide an earthing point with a metallic return path, the consumer's earthing terminal connects to it (11.6.26(i)). Otherwise the consumer connects to their own earth electrode (11.6.26(ii)).

Standard and RCDs

Standard

Nigerian Electricity Supply and Installation Standards (NESIS) Regulations 2015 (NERC/Reg/1/2015), referencing BS 7671:2008, IEC 60364-5-54 and NCP 9 (National Code of Practice on Earthing). A 2025 NESIS revision is in draft.

RCD rule

Earth-leakage protection is required in the switchgear controlling supply to every user-site installation (NESIS 7.2.11.1.1). For residual current devices, operating current times earth-loop impedance must not exceed 40 (11.6.18). No mA rating is stated.

Notes

No further notes.

Verified

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

MEN (TN-C-S) per AS/NZS 3000. Follows New Zealand practice.

Standard and RCDs

Standard

AS/NZS 3000 framework (PRIF); local adoption not confirmed

RCD rule

30 mA RCDs expected on domestic circuits per AS/NZS 3000

Notes

Adoption assumed from regional practice, not confirmed from an opened local regulator. Check local rules. No predominant arrangement is given because none is sourced.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

Supply neutrals are solidly earthed and installations must follow the AS3000 multiple earthed neutral (MEN) system of earthing.

Standard and RCDs

Standard

Australian Standards / AS3000 (AS/NZS 3000), via Norfolk Island Electricity Supply Regulations 1986

RCD rule

30 mA earth leakage breaker required for temporary supplies and for spa baths, spa pools and swimming pools (Electricity Supply Regulations 1986 regs 7, 31); general domestic scope follows AS/NZS 3000

Notes

System and predominant: verified (regs 4(3), 30(1)). RCD: verified for listed locations only.

Verified

Supply arrangements

Predominant

Not established

In use

Not recorded

No authoritative information found on the supply earthing arrangement.

Standard and RCDs

Standard

National standards not publicly available

RCD rule

Not confirmed; check local rules

Notes

No reliable public information on earthing practice.

Check local rules

Supply arrangements

Predominant

Not established

In use

TN-C-S, TT

Mixed practice.

Standard and RCDs

Standard

MKS HD 60364

RCD rule

30 mA RCD on socket circuits.

Notes

No authoritative source was found, so the systems shown are unconfirmed and no predominant arrangement is given. Check local rules.

Check local rules

Supply arrangements

Predominant

TN-C-S

In use

TN-C-S

Neutral is earthed by the utility and bonded to the earthing conductor at the service panel (NEC-style, functionally TN-C-S). US territory.

Standard and RCDs

Standard

US NEC, current edition (CNMI Electric Service Regulations, NMIAC 50-10-815)

RCD rule

GFCI on wet-area receptacles expected where NEC-derived rules apply; enforcement varies

Notes

Standard: verified. System and predominant: corroborated (CNMI regulation + NEC 250.24 summary). RCD: unverified.

Corroborated