Do I need a new consumer unit for an EV charger?

Not automatically. A new consumer unit is needed when your board can't safely take the charger's new circuit and the protection it requires, because of its condition, its rating or no room for compatible devices. Sometimes a separate EV unit avoids replacing it.

Five things to look at on your board before anyone visits

You can't settle this from the hallway, but a look at your consumer unit, also called a fuse box, tells you what to ask. Leave the cover on and note these:

• A spare way. A blank slot means there may be room for the charger's circuit. It proves less than it seems, because the IET warns that a device of similar size may still not be compatible.
• A button marked T or Test. That's the test button on an RCD, the device that cuts the power on a leakage fault. If there's no button, mention it when you call.
• The board's age. The IET says protective devices can be difficult to retrofit into an existing unit because of its age or lack of space. Our guide to what an old fuse box means covers the wider question.
• Plastic or metal. Consumer units in homes have had to be non-combustible since January 2016, but a plastic casing doesn't rule a board out, as the next section explains.
• Heat, scorching or a poor report. Signs of overheating count against the board. So does a C1 or C2 against it on your last EICR, which our guide to EICR codes explains.

Our EV charger installation work starts by checking these in person, along with the earthing and the load on your supply. We're based in Walthamstow, with electricians across East London and the rest of the capital.

What decides whether the old board can stay?

An old consumer unit can stay when it's in good enough condition for the extra circuit and the charger's protection can be added to it safely. Electrical Safety First's guidance for electricians says a new circuit can come from an existing all-insulated, meaning plastic, unit. The conditions are an adequate rating and condition, tight and correctly located connections, no overheating and no recalled parts.

Charging puts a long, steady load on the board

An EV charger is a continuous load. The IET gives it as an example of current sustained for several hours, and says designers have to allow for the heat these circuits add. Where a board already serves a continuous load, the designer must reassess its loading before adding a circuit.

An older RCD can make a spare way useless

The charging point needs an RCD of 30 mA or less, of Type A, F or B, either at the board or inside the charger. RCDs built into a charger's circuit board often don't meet the required standards, so check the exact model. The IET also says a Type AC RCD shouldn't sit upstream of a Type A, because direct current can blind it.

So a spare way behind a Type AC RCD may be no use to you, however empty the slot looks. That IET article was written to the 2022 edition, and BS 7671:2018+A4:2026 became the only valid version on 15 October 2026.

The IET describes an RDC-DD as a detection device for DC residual current, and says a Type A or F RCD can be used where the charger provides that protection. Ask for the design to follow the current text.

Keep the board, add a separate unit or replace it

The three ways to supply an EV charger are the existing board, a separate EV consumer unit, or a new main board. The IET says protection can be hard to retrofit because of a unit's age or lack of space, so installers sometimes fit a larger unit or a separate one instead. A separate unit still has to suit its supply, position and protection.

A separate unit doesn't belong in the meter box

With no room indoors, the empty space in an outside meter cabinet looks like the obvious spot. The IET's article quotes the Energy Networks Association on why it isn't:

"While the meter cabinet is the customer's, it is a space designed for the use of electricity industry apparatus only and no allowance is made for additional equipment."

An outdoor unit beside the cabinet is possible, using a product its maker has verified for outdoor use. The same IET article notes many engineers regard that as a "last resort" design option, so indoors is worth exploring first.

A new board doesn't add any supply

A new consumer unit doesn't increase your home's supply, because everything upstream of the board stays as it was. That includes the cut-out fuse and service cable, which the government's plan says can need upgrading in some homes. The cut-out fuse is the network operator's responsibility, not your electrician's.

Your installer has to work out the total load. The IET's webinar answers say that checking the incoming supply is a requirement of BS 7671, and that a total over 60 A including the charger needs permission from the network operator before installation. Its FAQ gives the same limit as 13.8 kVA of maximum demand.

Under that limit, the Energy Networks Association still has to be told afterwards. The IET's FAQ says within one month and its webinar answers say within 30 days, so ask your installer to confirm they've notified within that time. Electrical Safety First says the network operator must by law be informed, and that your installer should be able to do it for you.

If the total is too high, load curtailment, which limits what the charger can draw, is one answer. The IET warns that with two chargers in use at once it "may seriously affect the charging times".

Earthing is a separate question from the board

Your earthing arrangement decides how the charger is protected, and a new consumer unit doesn't change it. The IET says PME is the most common earthing type for new supplies. A broken shared conductor on that kind of supply, an open PEN fault, puts all connected metalwork at risk, and the IET sees a particular risk where a charge point is present.

BS 7671 doesn't ban a PME earth for outdoor charging, but the IET's FAQ, written to the 2020 edition, says one of five methods is needed:

• a balanced three-phase installation
• an additional earth electrode
• a device that disconnects the supply when the voltage between the protective conductor and earth exceeds 70 V
• a device that disconnects it when the supply voltage goes above 253 V or below 207 V
• an alternative with no lesser degree of safety

We identify your earthing type before designing anything, so ask any installer which method they plan to use under the current edition and why.

Three outcomes, priced from our guide

Our guide price for an EV charger is from £600, typically £600 to £1,000, with the charger included. A consumer unit replacement is from £400, typically £400 to £700. Both include VAT, and neither is a fixed quote for a home we haven't seen.

See what moves the cost of a new consumer unit if your survey lands on the second row. If it's the third, we'll price the unit once we've seen where it can go. Call 07727 619854 and we'll arrange the survey.

A new circuit and a new board are both notifiable work in England

In England, Building Regulations 2010, regulation 12(6A) makes a new circuit and a consumer unit replacement notifiable work, so every route here needs sign-off. The government's consultation response says a new charge point would generally include a new circuit.

NICEIC says Building Control has to be told 48 hours before work starts, unless your electrician is on a Competent Person Scheme and can self-certify. We're a NICEIC approved contractor, so that's on us, and we test and certify the work before handing it back.