Mark Kimberley, Residential Market Manager at Hager UK, identifies some of the frequently asked questions that are springing up in relation to the correct protection for heat pump installations.
Q. What distinguishes the Hager Type B HP from a standard Type B RCCB?
The Hager Type B HP is optimised for high-frequency leakage currents often present in heat pump inverter technology. It ensures tripping at 150 mA above 1 kHz and functionality with frequencies greater than 20 kHz. Standard Type B RCDs may not perform effectively in heat pump applications.
Q. Does BS 7671 specify special requirements for heat pumps?
No, heat pumps are not classified as a special installation within BS 7671. However, Regulation 134.1.1 requires good workmanship and proper materials shall be used.
The installation of electrical equipment shall take account of manufacturers’ instructions.
Q. Can I omit an RCD from heat pump installations, if I use a wiring method that does not require additional protection by 30 mA RCD?
This is not recommended and goes against the guidance detailed in the safety standard: BS EN IEC 60335-2- 40:2023+A11:2023 “Household and similar electrical appliances – Safety – Part 2-40: Particular requirements for electrical heat pumps, air-conditioners and dehumidifiers”
This standard, that includes heat pump installations, states that the use of an RCD not exceeding 30 mA is advisable.
Q. Can I use a B+ RCD instead of the Hager Type B HP?
No, Type B+ is a German VDE standard and not recognised by BS 7671.
Q. Can I install the Hager Type B HP RCCB in a consumer unit with devices from other manufacturers?
No. According to Regulation 536.4.203 of BS 7671, mixing protective devices from different manufacturers within a consumer unit is not permitted unless the manufacturer declares compatibility. Hager consumer units must be populated with Hager devices to ensure safety and compliance.
Q. Can I feed a Hager Type B HP RCCB from a Type A or AC RCD in a split-load consumer unit?
No. This violates RCD coordination principles. A Type B RCD must not be downstream of a Type A or AC RCD. Residual DC leakage could also cause the upstream Type AC RCD to become blinded, malfunction or fail to trip, compromising electrical safety.
Get more details and download Hager’s bite sized guide to RCDs for heat pumps here
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