{"id":18945,"date":"2026-06-05T08:17:34","date_gmt":"2026-06-05T08:17:34","guid":{"rendered":"https:\/\/tradefoxapp.com\/?p=18945"},"modified":"2026-06-05T08:20:31","modified_gmt":"2026-06-05T08:20:31","slug":"earth-bonding","status":"publish","type":"post","link":"https:\/\/tradefoxapp.com\/fr\/earth-bonding\/","title":{"rendered":"Earth Bonding In UK Homes: Main Bonding vs Supplementary, Where Inspectors Look First"},"content":{"rendered":"
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Earth bonding is one of those topics that sounds straightforward on paper and then catches half the trade out when it comes to inspection day. Inspectors fail installations every week over it. Not because the work is hard, but because the rules are misunderstood, the testing is skipped, or someone bonded a sink that never needed bonding while leaving the gas service sitting un-clamped six feet from the meter.<\/span><\/p>

This guide walks through the distinction between main protective bonding and supplementary bonding under BS 7671, what an inspector looks for first in a domestic property, and the small details that turn a satisfactory EICR into an unsatisfactory one.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Earthing vs Earth Bonding: Get The Terms Right\n<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Before anything else, the language matters. Earthing and bonding use the same green and yellow conductors, but they do entirely different jobs.<\/span><\/p>

Earthing connects exposed-conductive-parts (the metalwork of the electrical installation itself, such as metal enclosures, back boxes, and the consumer unit casing) to the Main Earthing Terminal (MET) so that a fault current has a path back to source. That path is what allows the protective device to operate.<\/span><\/p>

Earth bonding connects extraneous-conductive-parts (metal that is not part of the electrical installation but could introduce a potential into the building, typically incoming metallic gas and water pipes) to the same MET. The aim is to keep everything at the same potential during a fault, so a person touching two metal parts at once does not become the path between them.<\/span><\/p>

Le<\/span> IET defines an extraneous-conductive-part<\/a><\/strong> as “a conductive part liable to introduce a potential, generally Earth potential, and not forming part of the electrical installation.” All three conditions have to be met. That definition is the source of more EICR disagreements than almost any other point in the regs. <\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Main Protective Bonding: What BS 7671 Requires\n<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Main protective bonding is the non-negotiable part. Regulation 411.3.1.2 requires main protective bonding conductors to connect any extraneous-conductive-parts to the MET. In a typical UK domestic property, that means the incoming metallic gas pipe and the incoming metallic water pipe, plus any other service that introduces earth potential into the building (oil lines and structural steelwork can apply in some cases).<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Location Of The Bond\n<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Regulation 544.1.2 sets the location rule. The connection should be made as near as practicable to the point of entry, normally within 600mm of the meter outlet, on the consumer side, and before any branch or tee in the pipework. The exact wording in BS 7671 uses “where practicable,” which matters. If the meter cupboard geometry genuinely prevents a connection within 600mm, the closest practicable accessible point before the first branch is acceptable. The same 600mm guidance is mirrored in BS 6891:2015 clause 8.4.3.2 for gas installation pipework, and in<\/span> Gas Safe Register Technical Bulletin 102<\/a><\/strong>, which also recognises an external meter box termination as an acceptable alternative.<\/span><\/p>

What this means in practice:<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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