By WCED

WCED Type B RCD | 2 & 4 Pole, 25–63A, 30mA | EcoHarmony

£95.00 - £119.00
£95.00
£95.00
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Availability:
SKU: WEV225B-030
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The WCED Type B RCD provides residual current protection against AC, pulsating DC, and smooth DC fault currents — making it the correct choice for EV charger installations, heat pump circuits, inverter-driven loads, UPS systems, and frequency converters where standard Type A or Type AC devices may not provide sufficient protection.

Available in 2-pole (single-phase) and 4-pole (three-phase) configurations, with current ratings of 25A, 40A, and 63A. All variants are 30mA sensitivity and DIN rail mountable.

Correct protection for modern EV charger installations. Where an EV charger or associated equipment can produce smooth DC residual currents, a Type B RCD is required under IEC/EN 62423. Type A devices detect pulsating DC only and may not provide adequate protection in these scenarios. Your installer will confirm which type applies to your installation.

Which variant do you need?

Variant Poles Supply Typical use SKU
2 Pole 25A 2 Single phase Smaller single-phase EV charger or heat pump circuits WEV225B-030
2 Pole 40A 2 Single phase Standard 7kW single-phase EV charger installations WEV240B-030
2 Pole 63A 2 Single phase Higher-load single-phase circuits, submain protection WEV263B-030
4 Pole 25A 4 Three phase Smaller three-phase inverter or converter circuits WEV425B-030
4 Pole 40A 4 Three phase Three-phase EV chargers, solar inverters, UPS WEV440B-030
4 Pole 63A 4 Three phase Higher-load three-phase commercial EV installations WEV463B-030
2-pole vs 4-pole. Use the 2-pole variant for single-phase (230V) installations. Use the 4-pole variant for three-phase (400V) installations where all three phases plus neutral require monitoring. If you are unsure which applies, consult your installer or contact us.

Technical specifications

Specification 2 Pole variants 4 Pole variants
Poles 2 4
Current ratings available 25A, 40A, 63A 25A, 40A, 63A
Tripping sensitivity 30mA 30mA
RCD type Type B Type B
Fault current detection AC, pulsating DC, smooth DC AC, pulsating DC, smooth DC
AC frequency range Up to 1000Hz Up to 1000Hz
Rated voltage 230V 400V
Mounting 35mm DIN rail 35mm DIN rail
Standard IEC/EN 62423 IEC/EN 62423
Brand WCED WCED

Typical applications

  • EV charger installations — where the charger specification or inverter design requires Type B protection
  • Heat pump circuits — variable frequency drives can produce smooth DC leakage requiring Type B detection
  • Solar PV inverters — particularly transformerless inverters that can produce DC residual currents
  • UPS systems — uninterruptible power supplies with DC bus circuits
  • Frequency converters — industrial and commercial variable speed drives
  • Building site power cabins — where mixed load types require comprehensive residual current protection

Type A vs Type B — what is the difference?

Type A RCDs detect AC and pulsating DC residual currents. Type B RCDs detect all of the above plus smooth DC residual currents and AC currents at frequencies up to 1000Hz. For many modern EV chargers and inverter-driven loads, the equipment's internal power electronics can produce smooth DC leakage that a Type A device will not detect — making Type B the technically correct choice.

Not every EV charger installation requires Type B protection. The charger manufacturer's documentation will specify the required RCD type. If the documentation specifies Type A or Type AC, a Type A device is sufficient. If it specifies Type B, or if the charger contains a PFC stage or rectifier, Type B should be used.

Frequently asked questions

Does every EV charger need a Type B RCD?
No — it depends on the charger. Some EV chargers include internal DC fault protection (often called RDC-DD) which means a standard Type A RCD is sufficient upstream. Others, particularly those without internal DC protection or with specific inverter stages, require Type B. Always check the charger manufacturer's installation documentation and your installer will confirm the correct device. If in doubt, Type B provides a higher level of protection and is always acceptable where Type A is required.
What does 30mA tripping sensitivity mean?
30mA is the standard tripping threshold for personal protection — it will disconnect the circuit when residual current reaches 30 milliamps, which is below the threshold likely to cause a lethal electric shock in most circumstances. This is the standard sensitivity required for EV charger and domestic circuits under BS 7671.
Can I use a Type B RCD where a Type A is specified?
Yes. Type B provides a superset of the protection offered by Type A — it detects everything Type A detects, plus smooth DC currents. Using a Type B where Type A is specified is always technically acceptable, though it comes at a higher cost. Where the charger documentation specifies Type A, either type is compliant.
Does this RCD include overcurrent protection?
No. This is a standalone RCD (RCCB) providing residual current protection only. It does not include overcurrent or short-circuit protection. A separate MCB or RCBO is required for overcurrent protection, or the circuit must be protected upstream by an appropriately rated MCB. See our full WCED range for compatible overcurrent protection devices and pre-fitted consumer units.
Is this suitable for use in a pre-fitted consumer unit?
This is a standalone DIN rail module, not a pre-fitted unit. If you need a complete ready-to-connect solution with RCD, MCB or RCBO, and surge protection already assembled, see our pre-fitted EV charger consumer units.
What is the difference between the 2-pole and 4-pole versions?
The 2-pole variant is for single-phase (230V) installations — it monitors the live and neutral conductors. The 4-pole variant is for three-phase (400V) installations — it monitors all three phase conductors plus neutral. Use 2-pole for standard domestic EV chargers and single-phase heat pumps. Use 4-pole for three-phase EV chargers (11–22kW), three-phase heat pumps, and commercial installations.

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Single Phase PME Unit (IP65) 3-Phase PME Unit Pre-Fitted Consumer Units All WCED Products Product Finder
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