If you are looking at a UK installation then the minimum requirement under BS 7671 is covered in regulations group 464, "Switching off for mechanical maintenance".

461.1 Says that means "shall" be provided, & that it "shall" disconnect all live conductors.

So, if you are going to remove the local isolator from between the MCB and the heat pump, then for compliance with BS 7671 you will need to isolate at the DB, which must have a 2 (if single phase) or 4 (if 3 phase) pole main switch, as Neutral is a live and current carrying conductor, thus it must also be isolated.


As a heat pump is also machinery under the Machinery Directive, then a similar requirement is within EN 60204-1, so whichever way you argue the isolator, installation or machinery it is realistically required.

If the heat pump has a built in isolator then there is the possibility that this can meet the requirements.


Also the requirement under EN 60204-1 for means of isolation for maintenance is that means of emergency isolation are coloured red/yellow, isolation for maintenance would be coloured black/grey.

If you are looking at a UK installation then the minimum requirement under BS 7671 is covered in regulations group 464, "Switching off for mechanical maintenance".

461.1 Says that means "shall" be provided, & that it "shall" disconnect all live conductors.

So, if you are going to remove the local isolator from between the MCB and the heat pump, then for compliance with BS 7671 you will need to isolate at the DB, which must have a 2 (if single phase) or 4 (if 3 phase) pole main switch, as Neutral is a live and current carrying conductor, thus it must also be isolated.


As a heat pump is also machinery under the Machinery Directive, then a similar requirement is within EN 60204-1, so whichever way you argue the isolator, installation or machinery it is realistically required.

If the heat pump has a built in isolator then there is the possibility that this can meet the requirements.


Also the requirement under EN 60204-1 for means of isolation for maintenance is that means of emergency isolation are coloured red/yellow, isolation for maintenance would be coloured black/grey.