In our ASHP installations, the flow and return pipework runs above ground externally before entering the building. The heat pump is earthed via a CPC from the switch board, and the pipework is connected to the unit. As the external pipework is not buried and does not appear to be in contact with earth, we are assessing whether it constitutes an extraneous-conductive-part. Could anyone confirm if main protective bonding is required at the point of entry in line with BS 7671 Regulation 544.1.2? For our GSHP installations, the borehole pipework is plastic and remains non-metallic from the ground up. There is approximately 1.2 m of metal pipework externally above ground before entering the building and connecting to the system. As the external metal section is connected to plastic pipework and not in contact with earth, we believe it does not introduce earth potential and therefore would not be considered an extraneous-conductive-part. The GSHP unit is earthed via a CPC from the switch board. Can you confirm that in this case, main protective bonding is not required in accordance with BS 7671 Regulation 544.1.2? In a plantroom, where metal heating/chilled water pipework is installed entirely within the building and connected to heat pumps, and the heat pumps are earthed via a CPC, is main protective bonding required in this case?

Main Protective Bonding for Heat Pump Pipe works

Ishrath 19 hours ago

In our ASHP installations, the flow and return pipework runs above ground externally before entering the building. The heat pump is earthed via a CPC from the switch board, and the pipework is connected to the unit. As the external pipework is not buried and does not appear to be in contact with earth, we are assessing whether it constitutes an extraneous-conductive-part. Could anyone confirm if main protective bonding is required at the point of entry in line with BS 7671 Regulation 544.1.2?

For our GSHP installations, the borehole pipework is plastic and remains non-metallic from the ground up. There is approximately 1.2 m of metal pipework externally above ground before entering the building and connecting to the system. As the external metal section is connected to plastic pipework and not in contact with earth, we believe it does not introduce earth potential and therefore would not be considered an extraneous-conductive-part. The GSHP unit is earthed via a CPC from the switch board. Can you confirm that in this case, main protective bonding is not required in accordance with BS 7671 Regulation 544.1.2?

In a plantroom, where metal heating/chilled water pipework is installed entirely within the building and connected to heat pumps, and the heat pumps are earthed via a CPC, is main protective bonding required in this case?