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Heat Pump Protection Units Explained

Heat Pumps

Heat Pump Protection Units Explained

A heat pump protection unit is a small, pre-wired sub-board holding the protective devices a heat pump circuit needs, so you are not sourcing and wiring them one by one.

Quick answer

Choose between a standard Type B unit and a high-frequency Type B unit according to the heat pump manufacturer’s stated RCD requirement. Both include a Type 2 SPD and are fed from a way on the main consumer unit. For why, see heat pump electrical protection requirements.

What is inside

Standard Type B unit High-frequency Type B unit
RCD Type B Type B rated for higher-frequency leakage
Surge protection Type 2 SPD, pre-wired Type 2 SPD, pre-wired
Overcurrent protection MCB MCBs, with main switch
Suits Most residential inverter heat pumps VRF, commercial and some high-efficiency models where the manufacturer specifies a high-frequency RCD

Choosing the right unit

  1. Find the RCD requirement in the heat pump installation manual.
  2. Match the frequency rating. Standard Type B unless the manual specifies a high-frequency RCD.
  3. Check the overcurrent rating against the heat pump’s maximum input current.
  4. Confirm supply capacity, especially if an EV charger is on the same property.

Installing it

  • Feed the unit from a way on the main consumer unit through suitable overcurrent protection
  • Keep the SPD connections short and direct, see how to install an SPD
  • Test the RCD, and record the protection arrangement on the installation certificate

For the SPD connection rules, see how to install an SPD.

Shop heat pump protection units

Standard and high-frequency Type B versions, pre-assembled and tested.

Type B unitHigh-frequency unit

Frequently asked questions

Why is a pre-assembled unit worth it?

It arrives pre-wired and tested, so there is less to source and wire on site and fewer places for wiring errors.

Can I fit the unit outdoors?

The units are supplied in indoor enclosures. Check the enclosure rating against the mounting location, see IP40 vs IP65 enclosures.

Do I still need the manufacturer’s approval of the RCD type?

The manufacturer’s installation manual is the authority on the RCD required, so check it before you specify.

Heat PumpsHeat Pump Electrical Protection RequirementsHeat PumpsHeat Pump Tripping: Electrical or Heating Fault?RCDs & RCBOsWhat Is a Type B RCD?Enclosures & ComponentsIP40 vs IP65 Enclosures

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