I see little point in isolating PE as the outdoor unit is almost certainly linked to the indoor unit by copper pipes, that are bonded or earthed inside.

I see little point in isolating PE as the outdoor unit is almost certainly linked to the indoor unit by copper pipes, that are bonded or earthed inside.

The air-con units that I saw were pretty much self contained and were not bonded inside the building. The pipes just ran at high level from outside to the inside of the room and were boxed in. The units would of course be earthed.

I was thinking of a maintenance person being outside on a metal ladder and working on the internals of the outside unit. Of course he could also be contacting between the earthed metal work and ground.

Z.