Surge Protection for EV Chargers — UK Guide

EV charger electronics are particularly vulnerable to transient overvoltages. A Type 2 SPD at the consumer unit or EV distribution board protects the charger's control electronics, communication modules, and power supply — components that are expensive to replace and not always covered by warranty if surge damage is proven.

An EV charger is a significant investment — typically £500 to £1,500 installed — and it contains sensitive electronics including Wi-Fi and Bluetooth modules, microprocessor control boards, and communication interfaces. These components are exactly the type of equipment that surge events damage, often invisibly at first, with failures appearing weeks or months after the event that caused them.

A Type 2 SPD installed at the consumer unit or EV distribution board provides the first line of defence against surges arriving via the supply cable. The cost of the SPD is typically 2–5% of the charger installation cost — one of the most cost-effective forms of equipment protection available.

What surges affect EV chargers?

Surge source	How it reaches the charger	Risk level
Indirect lightning (nearby strike)	Via supply cables and earthing system	High — can cause immediate or latent failure
Grid switching transients	DNO switching of capacitor banks, transformers	Medium — frequent, lower energy
Motor switching (on same supply)	Internal — other equipment on same circuit	Low to medium
Welding or arc equipment nearby	Conducted via supply	High in industrial settings

Where to install the SPD

For a standard domestic EV charger installation, the SPD should be installed at the main consumer unit — this provides protection for all circuits including the EV supply. Where an EV distribution board or sub-board is installed (common for multi-charger or 3-phase installations), an SPD should also be installed at that board.

WCED EV connection units (WEVCU and WPEVCU series) and IP65 EV enclosures include a built-in Type 2 SPD as standard — no separate SPD is required where these products are used.

WCED SPD options for EV installations

WSPD240 — 2-pole 40kA Type 2 SPD

WSPD440 — 4-pole 40kA Type 2 SPD

WSPDT2-CB — 2-pole SPD with pre-fitted cable kit

WEVCU32BSP — 5-module EV unit with SPD built in

WPEVCU32BSP — IP65 EV unit with SPD built in

WME06/SP to WME28/SP — consumer units with SPD included

Shop WCED EV Protection Units with SPD

EV connection units with integrated surge protection — metal and IP65 weatherproof options. In stock.

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Frequently Asked Questions

Is surge protection required for EV chargers under BS 7671?

BS 7671 requires a risk assessment for surge protection on all installations. For a domestic property with an EV charger — expensive, sensitive electronics connected to the supply — the risk assessment almost always concludes that SPD protection is appropriate. Building Regulations Part P (England) now requires SPDs in new dwellings, which includes new EV charger installations in new builds.

Does an SPD void the EV charger warranty?

No — installing an SPD is a best practice measure that protects the charger. Surge damage is typically excluded from EV charger warranties, so an SPD actually helps protect your warranty by preventing the type of damage that warranty claims are rejected for.

Can I use the SPD in the EV connection unit instead of a separate one?

Yes — WCED EV connection units (WEVCU and WPEVCU series) include an integrated Type 2 SPD. If you are using one of these units, you do not need to install a separate SPD for the EV circuit. However, a separate SPD at the main consumer unit is still recommended to protect the rest of the installation.

Further reading:
Type 1 vs Type 2 vs Type 1+2 SPD explained
Do I need surge protection? 18th Edition guide
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