Helpful video reference. Adam Stears of SOTA Electrical in Fareham, Hampshire, tears out and rebuilds an existing EV charger installation that failed to meet current standards. His "I Rebuilt This EV Charger Installation From Scratch… Here's Why It Was WRONG." is a useful companion to this guide because it shows real examples of the faults described below, including missing open PEN protection and incorrect circuit protection, and explains how each fault was corrected to bring the installation into compliance.
1. Check for open PEN fault protection
This is the most safety-critical item. The majority of UK homes have a PME supply (also called TN-C-S). On a PME supply, a break in the neutral conductor in the street can cause the earth in your home to rise to a dangerous voltage. That voltage can appear at the vehicle and charger during what is known as an open PEN fault condition.
BS 7671:2018 and the OZEV grant conditions both require open PEN fault protection before an EV charger is connected to a PME supply. This protection either takes the form of a detection device built into the charger itself, or a separate OPF detector installed at the consumer unit as part of the charger supply circuit.
To check: read the label or data plate on the charger. Many modern chargers (Ohme, Hypervolt, Zappi, Wallbox, Pod Point Solo 3 and others) include built-in OPF detection and state this on the label or in their documentation. If the charger was installed before 2022 and no separate OPF device is visible at the consumer unit, there is a reasonable chance the protection is missing.
If your home has a TT supply (an earth electrode in the ground rather than a PME earth from the street), open PEN protection is not required in the same way, but the earth electrode must be sound and tested, with appropriate RCD protection on the charger circuit.
2. Inspect the dedicated circuit and protective device
A 7.4 kW single-phase EV charger draws up to 32 A continuously. It should be on its own dedicated radial circuit, not sharing the supply with any other load.
At the consumer unit, there should be a clearly labelled MCB or RCBO rated at 32 A for the EV charger circuit and nothing else. On a split-load board, the charger should ideally be on the appropriate RCD half. On a full RCBO board, the charger should have its own RCBO. A circuit shared with sockets, lighting or any other load is not compliant.
While you are looking at the consumer unit, check that the label on the breaker matches what is actually connected. Unlabelled boards or mislabelled circuits are a sign that the installation was not properly documented.
3. Assess cable sizing and routing
The cable from the consumer unit to the charger must be sized to carry 32 A with an acceptable volt drop. The minimum for most residential runs is 6 mm2 two-core and earth. Longer runs, or cables clipped to a surface without free air circulation, often need 10 mm2 to keep volt drop within the BS 7671 limit of 3% for final circuits.
Trace the cable from the consumer unit to the charger. Signs of a problem include:
- Thin cable that looks similar in diameter to a ring main cable (2.5 mm2) rather than the noticeably thicker 6 mm2 or 10 mm2 required.
- Joints or splices in the cable run outside of an accessible accessory.
- Cables buried in walls without being in conduit or following the safe zones defined in BS 7671 Appendix 1.
- External cable runs that are not in weatherproof conduit or trunking, or that are not armoured cable properly cleated.
4. Examine the physical installation quality
Step back and look at how the charger is mounted and the cable is managed.
A properly installed charger should be:
- Fixed to a solid wall, post or purpose-made bracket with appropriate fixings for the surface material (not just raw plugs into render).
- Level, with no visible flex or movement when the cable is inserted or removed.
- At an accessible height, with the cable outlet pointing downward or to the side to reduce the chance of water ingress.
Cable entries into the charger enclosure should be sealed. Any hole through a wall for the supply cable should be sleeved with conduit and made good on both sides. If the cable simply passes through an unsleeved hole in the brick or render, the installation is not properly finished.
5. Confirm earthing and bonding
Open the front cover of the charger (on most models a single screw or clip) if you are comfortable doing so, and check that the earth terminal has a green and yellow conductor connected. Do not probe or test anything live inside the charger, but a visual check that the earth wire is present and properly terminated is within reach of a careful homeowner.
At the consumer unit, confirm the main earthing conductor is intact and connected to the earth bar. If there are gas or water service entry points within 600 mm of the consumer unit, the main bonding conductors should also be present and in good condition.
6. Verify the completion documentation
An EV charger installation is notifiable work under the Building Regulations. The installer must have issued a Minor Works Certificate or, more commonly, a full Electrical Installation Certificate (EIC). This document records the circuit details, the test results, and the installer's details.
If the installation was funded through the OZEV Workplace Charging Scheme or the previous Electric Vehicle Homecharge Scheme, the grant application should also be on file.
Ask the installer or check your email and paperwork for the EIC. If none exists, either the work was not notified to Building Control (which is a breach of the Building Regulations) or the documentation has been lost. An electrician can carry out a condition inspection and issue a Minor Electrical Installation Works Certificate if the installation is found to be compliant, but they cannot back-date an original EIC.
When to call us
Richard covers EV charger inspections across Sandwich and east Kent. If you have moved into a property with an existing charger, or you have doubts about the quality of a recent installation, a standalone inspection visit will check each of the points above, identify any remedial work and give you a written record of the charger's current compliance status.
Concerned about an EV charger installation in east Kent?
Richard carries out EV charger condition inspections and remedial work across Sandwich and east Kent, with written reports issued on completion.
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