Main Earth Bonding Requirements for EV Charger Installations
If you are having an EV charger installed at your home, one of the safety checks we must carry out is verifying the main protective bonding in your property.
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This page explains what bonding is, why it matters, and what the regulations require.
What Is Main Protective Bonding?
Main protective bonding connects the incoming metal services in your property to the main earthing terminal (MET) of the electrical installation.
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This normally includes:
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Incoming water pipes
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Incoming gas pipes
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Other metallic services entering the building
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Bonding ensures that in the event of an electrical fault, dangerous voltages cannot appear between metal services and electrical equipment.
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Instead, the fault current flows safely to earth and protective devices disconnect the supply quickly.
What Does Main Earth Bonding Look Like, and how can I find it in my home?
Main protective bonding is usually a green and yellow earth cable connected to the incoming metal water or gas pipe using a metal earth clamp.
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These should be near your incoming water pipe, usually under the kitchen sink, and near you gas meter.
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These clamps are typically labelled “Safety Electrical Connection – Do Not Remove”.
Why This Is Important for EV Chargers
Electric vehicle chargers draw a large amount of power continuously and must comply with strict electrical safety regulations.
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Before installing a charger we must ensure that the existing electrical installation meets current safety standards, including:
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Adequate earthing
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Correct protective devices
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Proper main protective bonding
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If bonding is missing or undersized, we are required to upgrade it as part of the installation.
What The Regulations Say
The requirements for bonding are defined in BS 7671 (IET Wiring Regulations).
Relevant regulations include:
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Regulation 411.3.1.2 – Main protective bonding must be provided to incoming services.
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Regulation 544.1.1 – Specifies the minimum size of bonding conductors.
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Section 722 – Additional requirements for electric vehicle charging equipment.
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These rules ensure that installations remain safe under fault conditions.
What if we dont have the earth bonding, or a smaller size?
On the day of installation we will confirm whether the main earth bonding is adequate.
If bonding is missing or undersized, it may need to be installed or upgraded to a 10mm bonding conductor.
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This is required to comply with the BS 7671 Wiring Regulations, which ensure the electrical installation is safe for EV charging equipment.
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Where possible we will try to identify this before the installation date. If any upgrades are required, we will discuss this with you and confirm any additional costs before proceeding.
How Long Does Bonding Upgrading Take?
In most cases, upgrading or installing main protective bonding is a quick and straightforward job.
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Typically this involves installing a 10mm green and yellow bonding conductor between the incoming service pipe and the main earthing terminal.
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This normally takes around 15–30 minutes if access is straightforward.
EV Charger Installation in Norwich & Norfolk
If you are looking for EV charger installation in Norwich or Norfolk, Eclipse Electrical Solutions installs Ohme, Zappi and Hypervolt chargers across the region.
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Do I Need Earth Bonding For An EV Charger?
In most homes bonding is already present, but it must meet current standards before an EV charger can be installed. If bonding is missing or undersized, it will need to be upgraded to comply with BS 7671.