{"id":27985,"date":"2026-11-09T17:40:37","date_gmt":"2026-11-09T17:40:37","guid":{"rendered":"https:\/\/tradefoxapp.com\/?page_id=27985"},"modified":"2026-11-10T00:01:32","modified_gmt":"2026-11-10T00:01:32","slug":"quick-reference","status":"publish","type":"page","link":"https:\/\/tradefoxapp.com\/fr\/bs-7671\/quick-reference\/","title":{"rendered":"BS 7671 quick reference: key values and site checklists"},"content":{"rendered":"\n<style>\n.tfg-page{--fg:#1d1d1f;--fg2:#6e6e73;--line:#d2d2d7;--soft:#f5f5f7;--brand:#F15927;--brand-ink:#C2410C;font-family:-apple-system,BlinkMacSystemFont,\"SF Pro Text\",\"SF Pro Display\",\"Helvetica Neue\",Helvetica,Arial,sans-serif!important;color:var(--fg);-webkit-font-smoothing:antialiased;font-size:19px;line-height:1.58;letter-spacing:-.012em;text-align:left;background:#fff}\n.tfg-page *,.tfg-page *::before,.tfg-page *::after{box-sizing:border-box}\n.tfg-page h1,.tfg-page h2,.tfg-page h3,.tfg-page p,.tfg-page li,.tfg-page td,.tfg-page th,.tfg-page 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class=\"tfg-local\" aria-label=\"BS 7671 guide\"><div class=\"tfg-local-in\"><a class=\"tfg-local-title\" href=\"https:\/\/tradefoxapp.com\/bs-7671\/\">BS 7671 Guide<\/a><div class=\"tfg-local-links\"><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/amendment-4\/\">What&#x27;s new in Amendment 4<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/before-you-start\/\">Before you start<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/protection-against-electric-shock\/\">Electric shock<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/fire-arc-fault-and-surge\/\">Fire, arc and surge<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/cable-selection-and-sizing\/\">Cable sizing<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/earthing-and-bonding\/\">Earthing and bonding<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/special-locations\/\">Special locations<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/ev-solar-batteries-and-heat-pumps\/\">EV, solar and batteries<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/inspection-and-testing\/\">Inspection and testing<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/certificates-and-eicr-codes\/\">Certificates and codes<\/a><a href=\"https:\/\/tradefoxapp.com\/bs-7671\/quick-reference\/\" aria-current=\"page\">Quick reference<\/a><\/div><\/div><\/nav><article class=\"tfg\" data-title=\"BS 7671 quick reference: key values and site checklists\" data-desc=\"BS 7671:2018+A4:2026 cheat sheet for electricians: key dates, disconnection times, RCD and AFDD rules, test values, bonding sizes and EICR codes.\" data-slug=\"quick-reference\">\n  <p class=\"tfg-eyebrow\">BS 7671 Guide \u00b7 Section 11<\/p>\n  <h1>Quick reference<\/h1>\n  <p class=\"tfg-lede\">The numbers and checklists you reach for most, on one page. Every table is a Tradefox summary: use it to jog your memory, then confirm the detail in the current edition before you sign anything.<\/p>\n\n  <aside class=\"tfg-brief\">\n    <h2>In brief<\/h2>\n    <ul>\n      <li>BS 7671:2018+A4:2026 is the only current edition. The A2+A3 version was withdrawn on 15 October 2026.<\/li>\n      <li>Socket circuits up to 63 A and fixed-equipment circuits up to 32 A: 0.4 s on TN, 0.2 s on TT, at 230 V.<\/li>\n      <li>30 mA RCDs cover most domestic circuits. Choose the RCD type by the load, not by habit.<\/li>\n      <li>Insulation resistance on a 230\/400 V circuit: test at 500 V DC, 1 M\u03a9 minimum.<\/li>\n      <li>On PME, size main bonding from the supply neutral, not your earthing conductor.<\/li>\n      <li>Every table links to the full guide section for the reasons behind the numbers.<\/li>\n    <\/ul>\n  <\/aside>\n\n  <h2>Key dates for Amendment 4<\/h2>\n  <table class=\"tfg-table\">\n    <thead><tr><th>Date<\/th><th>What changed<\/th><th>What it means on site<\/th><\/tr><\/thead>\n    <tbody>\n      <tr><td>15 April 2026<\/td><td>BS 7671:2018+A4:2026 published<\/td><td>You could design to A4 from this day<\/td><\/tr>\n      <tr><td>15 October 2026<\/td><td>BS 7671:2018+A2:2022+A3:2024 withdrawn<\/td><td>New designs must follow A4<\/td><\/tr>\n      <tr><td>Designed before 15 October 2026<\/td><td>Transitional allowance<\/td><td>Work designed to A2+A3 may be finished and verified to that version<\/td><\/tr>\n      <tr><td>From 15 October 2026<\/td><td>Certificates and reports<\/td><td>New designs state BS 7671:2018+A4:2026 on the paperwork<\/td><\/tr>\n      <tr><td>Any time<\/td><td>Older installations<\/td><td>Not unsafe just because the standard moved on; no automatic upgrade needed<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n  <p class=\"tfg-reg\">Regulation references: BS 7671:2018+A4:2026 introduction (dates and transitional note). Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/amendment-4\/\">What changed in Amendment 4<\/a><\/p>\n\n  <h2>Maximum disconnection times (230 V)<\/h2>\n  <table class=\"tfg-table\">\n    <thead><tr><th>Circuit<\/th><th>TN system<\/th><th>TT system<\/th><\/tr><\/thead>\n    <tbody>\n      <tr><td>Final circuit up to 63 A with socket-outlets, or up to 32 A feeding only fixed equipment<\/td><td>0.4 s<\/td><td>0.2 s<\/td><\/tr>\n      <tr><td>Distribution circuit, or any other final circuit<\/td><td>5 s<\/td><td>1 s<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n  <p>RCD test on site: one AC test at the rated residual current (I<sub>\u0394n<\/sub>), whatever the RCD type. A general non-delay device must trip within 300 ms; a time-delayed S-type between 130 ms and 500 ms. The old 5 \u00d7 I<sub>\u0394n<\/sub> test is no longer required.<\/p>\n  <div class=\"tfg-note\"><strong>On site:<\/strong> on a TT installation the electrode resistance is usually too high for a fuse or MCB to clear a fault in time. That is why an RCD normally does the fault protection job on TT.<\/div>\n  <p class=\"tfg-reg\">Regulation references: 411.3.2.2, 411.3.2.3, 411.3.2.4, Table 41.1, 415.1.1, 643.8. Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/protection-against-electric-shock\/\">Protection against electric shock<\/a><\/p>\n\n  <h2>Where a 30 mA RCD is needed<\/h2>\n  <table class=\"tfg-table\">\n    <thead><tr><th>Where<\/th><th>Requirement<\/th><th>Can it be left off?<\/th><\/tr><\/thead>\n    <tbody>\n      <tr><td>Socket-outlets rated up to 32 A<\/td><td>30 mA additional protection<\/td><td>Only outside dwellings, for sockets ordinary persons and children aren&#8217;t likely to use, and only with a documented risk assessment<\/td><\/tr>\n      <tr><td>Mobile equipment up to 32 A used outdoors<\/td><td>30 mA additional protection<\/td><td>No<\/td><\/tr>\n      <tr><td>AC final circuits feeding luminaires in dwellings<\/td><td>30 mA additional protection<\/td><td>No<\/td><\/tr>\n      <tr><td>Cables in walls or partitions less than 50 mm deep, or in partitions with metal parts<\/td><td>Under 50 mm: safe zone plus 30 mA RCD. Metal-part walls: 30 mA RCD at any depth (and a safe zone if shallow). Or a 522.6.204 method instead<\/td><td>Yes, if the cable has an earthed metal covering, is in earthed metal conduit, or is SELV\/PELV. Check Table 52.1<\/td><\/tr>\n      <tr><td>Rooms with a bath or shower<\/td><td>Every circuit serving the room<\/td><td>No<\/td><\/tr>\n      <tr><td>Outdoor lighting the public can reach (street furniture and similar)<\/td><td>30 mA additional protection<\/td><td>Only if supplied by SELV<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n  <p class=\"tfg-reg\">Regulation references: 411.3.3, 411.3.4, 522.6 and Table 52.1, 701.411.3.3, 714.411.3.4. Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/protection-against-electric-shock\/\">Protection against electric shock<\/a><\/p>\n\n  <h2>Choosing the RCD type<\/h2>\n  <table class=\"tfg-table\">\n    <thead><tr><th>Type<\/th><th>What it can sense<\/th><th>Typical loads<\/th><\/tr><\/thead>\n    <tbody>\n      <tr><td>AC<\/td><td>Plain AC residual current only<\/td><td>Fixed equipment known to produce no DC, such as simple resistive heaters<\/td><\/tr>\n      <tr><td>A<\/td><td>AC plus pulsating DC<\/td><td>General domestic circuits: LED lighting, IT equipment, most appliances<\/td><\/tr>\n      <tr><td>F<\/td><td>Everything Type A senses, plus mixed-frequency current<\/td><td>Single-phase variable-speed kit: heat pumps, air conditioning, modern washing machines<\/td><\/tr>\n      <tr><td>B<\/td><td>Everything Type F senses, plus smooth DC<\/td><td>Three-phase drives and inverters; some PV, battery and EV set-ups<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n  <p>When RCDs are in series, the upstream device must not be blinded by DC that a downstream device lets through:<\/p>\n  <ul>\n    <li>No Type AC upstream of Type A, F or B.<\/li>\n    <li>No Type A upstream of Type F or B.<\/li>\n    <li>No Type F upstream of Type B.<\/li>\n  <\/ul>\n  <p>The one exception: a Type AC, A or F RCD may sit upstream of a Type B where the RCD manufacturer specifically declares the arrangement suitable. This comes from an informative note to Regulation 531.3.3, so check it and Figure A53.2 in your copy.<\/p>\n  <div class=\"tfg-warn\"><strong>Watch out:<\/strong> an EV charge point needs protection against DC fault current above 6 mA. If the charger doesn&#8217;t provide it, fit a Type B RCD, or a Type A or F with a separate DC detection device.<\/div>\n  <p class=\"tfg-reg\">Regulation references: 531.3.3, Figure A53.2, 722.531.3.101. Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/protection-against-electric-shock\/\">Protection against electric shock<\/a> and <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/ev-solar-batteries-and-heat-pumps\/\">EV, solar, batteries and heat pumps<\/a><\/p>\n\n  <h2>Where AFDDs are required<\/h2>\n  <p>The rule applies to single-phase AC final circuits supplying socket-outlets rated up to 32 A. Use AFDDs to BS EN 62606.<\/p>\n  <table class=\"tfg-table\">\n    <thead><tr><th>Premises<\/th><th>AFDD on those socket circuits<\/th><\/tr><\/thead>\n    <tbody>\n      <tr><td>High-rise residential: a domestic building with any storey more than 18 m above ground<\/td><td>Required<\/td><\/tr>\n      <tr><td>Houses in multiple occupation (HMOs)<\/td><td>Required<\/td><\/tr>\n      <tr><td>Purpose-built student accommodation<\/td><td>Required<\/td><\/tr>\n      <tr><td>Care homes<\/td><td>Required<\/td><\/tr>\n      <tr><td>All other premises<\/td><td>Recommended<\/td><\/tr>\n      <tr><td>EV charge-point circuits to BS EN 61851 with BS EN IEC 62196-2 connectors<\/td><td>Not required<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n  <p class=\"tfg-reg\">Regulation references: 421.1.7, 722.421.1.7.201. Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/fire-arc-fault-and-surge\/\">Fire, arc fault and surge protection<\/a><\/p>\n\n  <h2>Insulation resistance<\/h2>\n  <table class=\"tfg-table\">\n    <thead><tr><th>Circuit<\/th><th>Test voltage (DC)<\/th><th>Minimum reading<\/th><\/tr><\/thead>\n    <tbody>\n      <tr><td>SELV and PELV<\/td><td>250 V<\/td><td>0.5 M\u03a9<\/td><\/tr>\n      <tr><td>Up to 500 V, including FELV (normal 230\/400 V work)<\/td><td>500 V<\/td><td>1 M\u03a9<\/td><\/tr>\n      <tr><td>Above 500 V<\/td><td>1000 V<\/td><td>1 M\u03a9<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n  <div class=\"tfg-note\"><strong>On site:<\/strong> if an SPD or sensitive kit can&#8217;t be disconnected, you may test that circuit at 250 V DC. The 1 M\u03a9 minimum still applies. A new circuit that only just passes deserves a closer look.<\/div>\n  <p class=\"tfg-reg\">Regulation references: 643.3, Table 64. Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/inspection-and-testing\/\">Inspection and testing<\/a><\/p>\n\n  <h2>Voltage drop limits<\/h2>\n  <table class=\"tfg-table\">\n    <thead><tr><th>Installation fed from the public LV network<\/th><th>Limit<\/th><th>At 230 V<\/th><\/tr><\/thead>\n    <tbody>\n      <tr><td>Lighting<\/td><td>3%<\/td><td>6.9 V<\/td><\/tr>\n      <tr><td>Other uses (power, heating)<\/td><td>5%<\/td><td>11.5 V<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n  <p>Limits are measured from the origin of the installation to the furthest point. Installations on a private supply are allowed more; check Table 4Ab for the figures.<\/p>\n  <p class=\"tfg-reg\">Regulation references: Section 525, Appendix 4 (Table 4Ab). Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/cable-selection-and-sizing\/\">Cable selection and sizing<\/a><\/p>\n\n  <h2>Main protective bonding: minimum copper sizes<\/h2>\n  <table class=\"tfg-table\">\n    <thead><tr><th>Supply arrangement<\/th><th>Minimum main bonding conductor<\/th><\/tr><\/thead>\n    <tbody>\n      <tr><td>Not PME (TN-S, TT)<\/td><td>Half the earthing conductor size, never below 6 mm\u00b2; need not exceed 25 mm\u00b2<\/td><\/tr>\n      <tr><td>PME, supply neutral 35 mm\u00b2 or less<\/td><td>10 mm\u00b2<\/td><\/tr>\n      <tr><td>PME, supply neutral 50 mm\u00b2<\/td><td>16 mm\u00b2<\/td><\/tr>\n      <tr><td>PME, supply neutral 70 mm\u00b2<\/td><td>25 mm\u00b2<\/td><\/tr>\n      <tr><td>PME, larger supplies<\/td><td>Check Table 54.8<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n  <div class=\"tfg-warn\"><strong>Watch out:<\/strong> the network operator can ask for a bigger bonding conductor than the minimum. Check their requirements before you buy the cable.<\/div>\n  <p class=\"tfg-reg\">Regulation references: 544.1.1, Table 54.8. Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/earthing-and-bonding\/\">Earthing and bonding<\/a><\/p>\n\n  <h2>EICR observation codes<\/h2>\n  <table class=\"tfg-table\">\n    <thead><tr><th>Code<\/th><th>Meaning<\/th><th>What happens next<\/th><\/tr><\/thead>\n    <tbody>\n      <tr><td>C1<\/td><td>Danger present, risk of injury now<\/td><td>Act straight away; make safe before you leave if you can<\/td><\/tr>\n      <tr><td>C2<\/td><td>Potentially dangerous<\/td><td>Urgent remedial work<\/td><\/tr>\n      <tr><td>C3<\/td><td>Improvement recommended<\/td><td>Not dangerous; the report can still be satisfactory<\/td><\/tr>\n      <tr><td>FI<\/td><td>Further investigation advised<\/td><td>Advisory under A4: on its own, an FI does not make the report unsatisfactory. Use it rarely, and never for things you can code, such as low insulation resistance or an unidentified circuit.<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n  <p>In privately and socially rented homes in England, landlords must get remedial or investigative work done within 28 days, or sooner if the report says so. GOV.UK guidance still treats FI as needing investigation, so tell landlords to follow every FI up.<\/p>\n  <p class=\"tfg-reg\">Regulation references: 653.1, 653.2, Appendix 6. Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/certificates-and-eicr-codes\/\">Certificates and EICR codes<\/a><\/p>\n\n  <h2>Pre-energisation checklist<\/h2>\n  <p>Do these with the supply off, in this order, before anything goes live:<\/p>\n  <ol>\n    <li>Inspection complete: terminations tight, barriers fitted, cables supported, labels on.<\/li>\n    <li>Continuity of protective conductors, including main and supplementary bonding.<\/li>\n    <li>Ring final circuits: end-to-end and cross-connected readings.<\/li>\n    <li>Insulation resistance at the right test voltage, sensitive kit disconnected.<\/li>\n    <li>Polarity: switches and single-pole devices in the line conductor only.<\/li>\n    <li>Earth electrode resistance on TT installations.<\/li>\n    <li>Only then energise, and move on to Z<sub>e<\/sub>, Z<sub>s<\/sub>, fault current, RCD and functional tests.<\/li>\n  <\/ol>\n  <p class=\"tfg-reg\">Regulation references: Chapter 64, Section 643. Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/inspection-and-testing\/\">Inspection and testing<\/a><\/p>\n\n  <h2>Safe isolation checklist<\/h2>\n  <ol>\n    <li>Identify the right circuit and the right isolation point.<\/li>\n    <li>Switch off and isolate.<\/li>\n    <li>Lock off, keep the key on you, and fit a warning label.<\/li>\n    <li>Prove your voltage indicator works on a known live source or proving unit.<\/li>\n    <li>Test dead between every combination of line, neutral and earth.<\/li>\n    <li>Prove the indicator again, straight after the dead test.<\/li>\n    <li>Only now start work.<\/li>\n  <\/ol>\n  <div class=\"tfg-warn\"><strong>Watch out:<\/strong> a multimeter or non-contact tester is not a substitute for a two-pole voltage indicator with probes that meet HSE GS38.<\/div>\n  <p class=\"tfg-reg\">Regulation references: Section 537 (isolation and switching); Electricity at Work Regulations 1989, regulations 12 and 13. Full guide: <a href=\"https:\/\/tradefoxapp.com\/bs-7671\/inspection-and-testing\/\">Inspection and testing<\/a><\/p>\n\n  <aside class=\"tfg-tools\">\n    <h2>Tradefox tools<\/h2>\n    <ul>\n      <li><a href=\"https:\/\/tradefoxapp.com\/calculators\/electrical\/loop-impedance-and-operating-current\/\">Loop impedance and operating current<\/a><\/li>\n      <li><a href=\"https:\/\/tradefoxapp.com\/calculators\/electrical\/calculated-earth-fault-loop-impedance\/\">Calculated earth fault loop impedance<\/a><\/li>\n      <li><a href=\"https:\/\/tradefoxapp.com\/calculators\/electrical\/tt-resistance-and-residual-current-relationship\/\">TT resistance and residual-current relationship<\/a><\/li>\n      <li><a href=\"https:\/\/tradefoxapp.com\/calculators\/electrical\/voltage-drop-as-a-percentage\/\">Voltage drop as a percentage<\/a><\/li>\n      <li><a href=\"https:\/\/tradefoxapp.com\/calculators\/electrical\/voltage-drop-using-mv-a-m\/\">Voltage drop using mV\/A\/m<\/a><\/li>\n      <li><a href=\"https:\/\/tradefoxapp.com\/calculators\/electrical\/ring-continuity-equal-line-and-neutral\/\">Ring continuity: equal line and neutral<\/a><\/li>\n      <li><a href=\"https:\/\/tradefoxapp.com\/calculators\/electrical\/adiabatic-protective-conductor-calculation\/\">Adiabatic protective conductor calculation<\/a><\/li>\n      <li><a href=\"https:\/\/tradefoxapp.com\/courses\/\">Tradefox courses<\/a><\/li>\n    <\/ul>\n  <\/aside>\n<\/article><nav class=\"tfg-pager\" aria-label=\"Guide sections\"><a class=\"tfg-prev\" href=\"https:\/\/tradefoxapp.com\/bs-7671\/certificates-and-eicr-codes\/\"><span>Previous<\/span>\u2039 Certificates and codes<\/a><a class=\"tfg-all\" href=\"https:\/\/tradefoxapp.com\/bs-7671\/\">All sections<\/a><span><\/span><\/nav><div class=\"tfg-legal\"><p><strong>Important.<\/strong> This guide is written by Tradefox to help qualified electricians understand BS 7671:2018+A4:2026. It is a plain-English summary for learning and reference only. It is not the standard, it does not reproduce it, and it is not professional advice. Always work to the current edition of BS 7671, the IET guidance notes, manufacturers\u2019 instructions, Building Regulations and your scheme provider\u2019s requirements. Electrical work must be carried out by a competent person.<\/p><p>To the extent permitted by law, Tradefox accepts no liability for loss or damage arising from use of this guide. BS 7671 is published by the IET and BSI; Tradefox is not affiliated with or endorsed by either. See our <a href=\"https:\/\/tradefoxapp.com\/terms-of-use\/\">Terms of Use<\/a>. Spotted something out of date? Email <a href=\"mailto:info@tradefoxapp.com\">info@tradefoxapp.com<\/a>.<\/p><\/div><script type=\"application\/ld+json\">{\"@context\": \"https:\/\/schema.org\", \"@type\": \"TechArticle\", \"headline\": \"BS 7671 quick reference: key values and site checklists\", \"description\": \"BS 7671:2018+A4:2026 cheat sheet for electricians: disconnection times, RCD and AFDD rules, test values, bonding sizes, EICR codes and site checklists.\", \"url\": \"https:\/\/tradefoxapp.com\/bs-7671\/quick-reference\/\", \"inLanguage\": \"en-GB\", \"author\": {\"@type\": \"Organization\", \"name\": \"Tradefox\", \"url\": \"https:\/\/tradefoxapp.com\/\"}, \"publisher\": {\"@type\": \"Organization\", \"name\": \"Tradefox\", \"url\": \"https:\/\/tradefoxapp.com\/\"}, \"datePublished\": \"2026-11-09\", \"dateModified\": \"2026-11-09\", \"about\": {\"@type\": \"Thing\", \"name\": \"BS 7671:2018+A4:2026 IET Wiring Regulations\"}, \"isPartOf\": {\"@type\": \"CreativeWorkSeries\", \"name\": \"Tradefox BS 7671 Guide\", \"url\": \"https:\/\/tradefoxapp.com\/bs-7671\/\"}, \"audience\": {\"@type\": \"Audience\", \"audienceType\": \"Electricians\"}}<\/script><\/div>\n","protected":false},"excerpt":{"rendered":"<p>BS 7671:2018+A4:2026 cheat sheet for electricians: disconnection times, RCD and AFDD rules, test values, bonding sizes, EICR codes and site checklists.<\/p>","protected":false},"author":1,"featured_media":0,"parent":27974,"menu_order":11,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"no-sidebar","site-content-layout":"","ast-site-content-layout":"full-width-container","site-content-style":"unboxed","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_glsr_average":0,"_glsr_ranking":0,"_glsr_reviews":0,"footnotes":"","_tfcalc_title":"BS 7671 Cheat Sheet: Key Values and Checklists | Tradefox","_tfcalc_desc":"BS 7671:2018+A4:2026 cheat sheet for electricians: disconnection times, RCD and AFDD rules, test values, bonding sizes, EICR codes and site checklists."},"class_list":["post-27985","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.8 - 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