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Fully Assembled WCED Consumer Units for EV Charging — Explained

Consumer Units

Fully Assembled Consumer Units for EV Charging

A fully assembled protection unit puts the protective devices an EV charging circuit needs into one pre-wired, pre-tested enclosure, so there is less to source, wire and get wrong on site.

Quick answer

An external PEN fault protection assembly may suit a charger without suitable integrated open-PEN protection. Check the charger manual and select the required circuit protection for the installation.

What is inside

Component What it does Guide
PEN fault detection Monitors the supply and disconnects the charger if the PEN conductor fails, typically when voltage leaves roughly 207V to 253V PME guide
RCBO Earth-leakage (30mA) and overcurrent protection for the charger circuit RCBO vs MCB vs RCD
Type 2 SPD Protects against transient overvoltages from lightning and switching Surge protection for EV chargers
Enclosure IP40 metal for indoor locations, or IP65 plastic for outdoor and exposed ones, depending on the unit IP40 vs IP65

These protect against three different fault types. PEN fault detection handles loss of the supply’s combined neutral-earth conductor. The RCBO handles faults inside the circuit. The SPD handles surges. None of them replaces another.

Why a pre-assembled unit

Built on site from separate parts Fully assembled unit
Sourcing PEN device, RCBO, SPD and enclosure bought separately All in one unit
Compatibility Installer confirms the devices work together Assembled and tested as a system
Wiring on site Internal wiring plus connections Supply and load connections only
Documentation Records for each device One set for the unit

Check the RCD type the charger needs

Many EV chargers include their own DC leakage detection (RDC-DD), which allows a Type A RCBO. Others need a Type B device, or an external RDC-DD. Always check the charger manual. See What is a Type B RCD?

Where it fits

  1. Feed from the main consumer unit. A dedicated circuit, protected at the board, runs to the unit.
  2. Mount the unit near the charger with the enclosure rating to suit the location.
  3. Connect the charger downstream. Follow the unit and charger instructions.
  4. Test and certify. Test the RCBO and the PEN fault function, and record the arrangement on the installation certificate.

Which unit

  • Single-phase 7kW charger: a single-phase unit
  • Three-phase 11kW or 22kW charger: a three-phase unit
  • Charger with built-in open-PEN protection: no PEN function needed, check what else the circuit requires

For selection detail, see PME protection devices and the WCED range comparison.

Shop fitted protection units

Single-phase and three-phase units with PEN fault detection, RCBO and surge protection.

Single-phase boards3-phase boardsPME protection

Frequently asked questions

Will a fully assembled unit work with any charger?

It sits upstream of the charger, so it is independent of the charger brand. Check the charger manual for its own protection and RCD-type requirements, as some chargers already include PEN fault detection.

Does it replace an earth rod?

A PEN fault detection function is one of the recognised alternatives to an earth electrode under BS 7671 Reg 722.411.4.1.

Is surge protection included?

Most units include a Type 2 SPD, but check the specific product, as some options add it separately.

Single-phase or three-phase?

Match the unit to the charger and supply: single-phase for a 7kW charger on a single-phase supply, three-phase for 11kW or 22kW chargers.

PME & EarthingPME Protection Devices Instead of an Earth RodPME & EarthingWhat Is PME in EV Charging?Consumer UnitsWCED Range Comparison: RCBO, SPD and PME UnitsDistribution BoardsTPN 3-Phase Distribution Boards Explained

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