Type B RCDs for EV Chargers, Heat Pumps & Inverters
Type B RCDs are used where electrical equipment may produce smooth DC residual current or high-frequency leakage. They are commonly specified for EV charger installs, heat pump supplies, solar inverters, UPS systems, drives and other inverter-led equipment.
Compared with Type A or Type AC devices, a Type B RCD gives wider residual current detection where DC leakage needs to be considered. This makes it an important option for installers working on modern renewable, EV and three-phase systems.
Quick answer: A Type B RCD is normally specified where equipment can produce smooth DC leakage, such as some EV chargers, heat pumps, solar inverters, UPS systems and variable speed drives. Always check the equipment manufacturer’s instructions and circuit design before selecting the RCD type.
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This range includes 2 pole Type B RCDs for single-phase applications and 4 pole Type B RCDs for three-phase systems. They are suited to installations where standard RCD selection needs to account for DC residual current behaviour.
- DC leakage detection – suitable where smooth DC residual current must be considered
- 2P and 4P options – for single-phase and three-phase installations
- EV and renewables ready – commonly used with EV chargers, solar inverters and heat pump circuits
- Installer-focused protection – useful for modern inverter-driven equipment and specialist loads
For related protection, view our standard RCDs, RCBOs, EV-ready consumer units and heat pump consumer units.
Heat Pump Consumer Unit 12 Way (WME12/HP40C)
£222.00
Pre-wired in the UK and tested before dispatch – allow up to 3 working days for shipping. The WME12/HP40C Heat Pump Consumer Unit is a dedicated 12-way protection board designed for inverter-driven heat pump systems. It comes pre-fitted with a 40A Type B RCD, a...
2 Pole B-Type RCD – WEV263B-030 (63A, 30mA)
£125.00
£148.00
The WEV263B-030 is a 2 Pole Type B RCD (63A, 30mA) designed for higher-load single-phase installations where smooth DC residual currents or high-frequency leakage may be present. Unlike Type A RCDs, it safely detects AC, pulsed DC, and smooth DC faults up to 1000 Hz,...
WME06/SP-B10063 - 6 Way Metal Unit with 100A B Type RCD & 63A MCB
£124.50
The WME06/SP-B10063 is a compact 6 module steel enclosure pre-assembled with a 100A B-Type RCD and 63A MCB. Built to order, this unit is designed to provide a ready-to-fit protection solution for EV installs, surge protection upgrades, or small distribution requirements. Housed in a robust...
Heat Pump Consumer Unit 10 Way (WME10/HP40R16)
£224.90
Pre-wired in the UK and tested before dispatch – allow up to 3 working days for shipping. The WME10/HP40R16 Heat Pump Consumer Unit is a dedicated protection board for inverter-driven heat pump systems. It comes pre-fitted with a 40A Type B RCD, a 16A MCB,...
4 Pole B-Type RCD – WEV463B-030 (63A, 30mA)
£158.30
The WEV463B-030 is a 4 Pole Type B RCD (63A, 30mA) designed for higher-load applications where smooth DC and high-frequency leakage currents may be present. Unlike Type A RCDs, it detects AC, pulsed DC, and smooth DC residual currents up to 1000 Hz, ensuring full...
When Should You Use a Type B RCD?
A Type B RCD is used where the connected equipment may generate smooth DC residual current or higher-frequency leakage that needs to be detected correctly. This is why Type B devices are commonly specified for EV charging, solar PV inverters, heat pumps, UPS systems and variable speed drives.
The exact RCD type should always be checked against the equipment manufacturer’s instructions, the circuit design and the wider installation requirements. The key point is simple: where smooth DC residual current is possible, standard Type AC or Type A protection may not be suitable on its own.
Type B RCD Applications
- EV chargers – often used where the charger does not provide the required DC leakage detection internally
- Heat pumps – useful for inverter-driven heat pump circuits where DC residual current may need to be considered
- Solar inverters – commonly specified where inverter behaviour requires DC-sensitive residual current protection
- UPS systems – suitable for specialist supplies with electronic conversion equipment
- Variable speed drives – used where drives and frequency converters may produce residual currents outside standard AC fault patterns
Type B RCD vs Type A RCD
The main difference is the type of residual current each device is designed to detect. A Type A RCD detects AC and pulsating DC residual current. A Type B RCD is designed for wider detection, including smooth DC residual current.
| RCD Type | Detects | Typical Use |
|---|---|---|
| Type AC | AC residual current | Basic AC loads only |
| Type A | AC and pulsating DC residual current | Many modern domestic and commercial circuits |
| Type B | AC, pulsating DC and smooth DC residual current | EV chargers, heat pumps, solar inverters, UPS systems and drives |
2 Pole and 4 Pole Type B RCDs
Choose the pole configuration based on the supply and installation design. 2 pole Type B RCDs are typically used for single-phase circuits, while 4 pole Type B RCDs are used on three-phase systems where all live conductors require residual current protection through the device.
- 2 pole Type B RCDs – commonly used on single-phase EV, solar and heat pump circuits
- 4 pole Type B RCDs – used for three-phase inverter-led equipment and commercial supplies
- 30mA Type B RCDs – commonly selected where additional protection is required, subject to the circuit design
Type B RCDs for EV Chargers
Some EV chargers include built-in DC leakage detection. Others require external protection to be selected correctly. Where the charger does not provide the required DC detection internally, a Type B RCD for EV charger installations may be required.
For pre-configured EV protection options, view our EV-ready consumer units and PME fault detection units.
Type B RCDs for Heat Pumps and Solar Inverters
Heat pumps and solar inverters both use electronic conversion equipment, which can affect residual current behaviour. Where manufacturer guidance or the circuit design calls for DC-sensitive protection, a Type B RCD for heat pump or Type B RCD for solar inverter use may be the correct choice.
For full board options, browse our heat pump consumer units and surge protection devices.
Type B RCD FAQs
What is a Type B RCD?
A Type B RCD is a residual current device designed to detect AC, pulsating DC and smooth DC residual currents. It is commonly used with inverter-driven equipment.
When do I need a Type B RCD?
You may need a Type B RCD where equipment can produce smooth DC residual current, such as certain EV chargers, heat pumps, solar inverters, UPS systems and variable speed drives.
Can I use a Type A RCD instead of Type B?
Only where the equipment manufacturer and circuit design allow it. If smooth DC residual current needs to be detected by the external RCD, Type B protection is normally required.
Are Type B RCDs used for EV chargers?
Yes. Type B RCDs are often used for EV charger circuits where the charger does not already provide suitable DC leakage detection internally.
Are Type B RCDs used for heat pumps?
Yes, they can be used for heat pump circuits where inverter-driven equipment creates a need for DC-sensitive residual current protection.
What is the difference between 2 pole and 4 pole Type B RCDs?
2 pole Type B RCDs are typically used for single-phase circuits. 4 pole Type B RCDs are used for three-phase systems.
UK-Stocked Type B RCDs for Trade Installs
Power & Data UK supplies 2 pole and 4 pole Type B RCDs for EV, heat pump, solar, UPS and inverter-led installations. Products are UK-stocked, with free UK mainland next-day delivery available on orders over £30 when placed before 2pm.