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How-to · UK domestic

How to fit a 32A Commando socket for EV charging

A 32A industrial Commando socket on a dedicated circuit is an affordable way to begin EV charging at home before a smart charger is fitted. It is not a permanent solution for most households - smart chargers offer load management, time-of-use scheduling and open PEN protection that a socket cannot - but for occasional charging or while planning a full installation, it is a properly wired circuit using a recognised standard socket type. Here is what the job involves.

Helpful video reference. The video above from Noorband electrical services shows a 32A Commando socket being installed for an EV charging point in a UK domestic property. It demonstrates the dedicated circuit approach, consumer unit connection and the socket termination. A useful visual reference for understanding what the job looks like in practice.

Before you start. Installing a new circuit is notifiable work under Part P Building Regulations. It must be carried out by, or notified by, a registered electrician. Adding a new circuit to a consumer unit involves working inside a live distribution board - safe isolation of the main switch is essential. This guide describes what the work involves; it is not a DIY instruction for unqualified homeowners.

1. Confirm whether a Commando socket is appropriate

A 32A Commando socket (CEE 7/44 style, IP44 or IP67 rated, three-pin) will charge an EV using a Mode 2 portable EVSE (the "granny charger" cable supplied with many vehicles). Maximum charge rate is approximately 7.2kW, which gives around 25-30 miles of range per hour for a typical EV.

What a Commando socket does not provide: smart load management (which prevents tripping the main fuse at peak demand), time-of-use scheduling, or the open PEN fault protection required by BS 7671 Section 722 for dedicated EV charger circuits on TN-C-S (PME) supplies. If you are applying for the OZEV home charging grant, you need an OZEV-approved smart charger, not a Commando socket. Discuss the long-term plan with your electrician before committing.

2. Plan the circuit and cable size

A 32A radial circuit from the consumer unit to the Commando socket uses 6mm² twin-and-earth cable. Under typical conditions - clipped to a surface in free air - 6mm² cable has a current-carrying capacity well above 32A, giving ample headroom. The design current for a 32A socket circuit is 32A.

Apply correction factors from the On-Site Guide for the actual installation method: factor Ca for ambient temperature (usually 1.0 for UK garage or driveway environments), factor Cc for enclosed or buried cable, and factor Cg for grouping with other cables. If the cable passes through an insulated wall cavity, the derating can be significant - check this carefully before assuming 6mm² is adequate.

Plan the cable route to avoid the prescribed cable safe zones where possible, or use mechanical protection where the route must cross them. In a garage, surface-mounted steel conduit is a clean, protected option.

3. Isolate the consumer unit safely

Switch off the main switch at the consumer unit. If the board has a hasp, lock it out. Test at the intended connection point - the bus bar or the spare way where the new RCBO will sit - using a calibrated voltage tester. In a split-load board, both RCD sections may need to be off before the bus bar is dead throughout. Confirm dead at all terminals before opening the board any further.

4. Fit the 32A RCBO in the consumer unit

A 32A Type A RCBO provides both overcurrent protection (replacing the MCB function) and 30mA RCD protection in a single device. For a socket circuit that will be used for EV charging, Type A is the minimum required under BS 7671 - it detects both AC and pulsating DC residual fault currents, which portable EVSEs can produce.

Clip the RCBO into a spare way in the consumer unit. Connect the incoming live to the line terminal and the outgoing live to the load terminal. Connect the neutral to the neutral bar and the circuit earth to the earth bar. If the board is full, you will need to either fit a larger consumer unit or remove a circuit that can be grouped with another - discuss this with the homeowner before starting.

5. Run the 6mm² cable to the socket position

Route the cable from the consumer unit to the socket position. Clip at intervals not exceeding those in the On-Site Guide for the cable size and installation method. Use steel or PVC conduit where the cable is exposed to mechanical damage. Where the cable passes through walls, use a conduit sleeve or grommet to protect the sheath.

At the socket end, leave enough cable to reach the terminals comfortably and make the connections without strain on the conductors.

6. Connect and mount the Commando socket

Strip the outer sheath of the cable to a depth that allows each conductor to reach its terminal cleanly. Strip each conductor to the terminal stripping depth marked inside the socket housing. Connect brown to the line (L) terminal, blue to the neutral (N) terminal, and green-and-yellow to the earth (E) terminal. Tighten each terminal screw to the manufacturer's torque specification.

For outdoor or driveway installations, use an IP67-rated socket with a surface mounting box. Fix the mounting box to the wall with stainless steel screws and plug the cable entry with an IP-rated gland. The socket should be positioned at a height that keeps it accessible but out of reach of floodwater and away from where a vehicle would park directly over it.

7. Test the circuit and label up

Before restoring power, carry out the required initial verification tests: continuity of the circuit protective conductor, insulation resistance between line and earth and between neutral and earth (minimum 1 MOhm at 500V DC for a new circuit), polarity check, and earth fault loop impedance (Zs) at the socket. Record all results on the test schedule.

Restore power and test the RCBO operation with the test button. Label the circuit in the consumer unit clearly - "32A EV socket garage" or similar. Notify the installation through your competent person scheme and issue the homeowner with a Minor Works Certificate or Electrical Installation Certificate as appropriate for the scope of work.

Stop and call an electrician if: the consumer unit is full and you are unsure which circuit to remove, the cable correction factors reduce the 6mm² capacity below 32A, the socket position is outdoors on a TN-C-S (PME) supply where open PEN protection is required but not available at this socket, or the homeowner is applying for the OZEV grant (which requires an approved smart charger, not a Commando socket).

When to call us

Richard fits 32A Commando sockets for EV charging across east Kent, as well as full smart charger installations for homeowners who want load management and time-of-use scheduling. Small local jobs are £10 per 10 minutes; a new circuit installation is a fixed-price quote job - get in touch to discuss.

EV socket or smart charger in Sandwich?

Richard can fit a 32A Commando socket as an interim solution, or install a full smart EV charger with open PEN protection and smart scheduling.

Contact Richard

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