greenhouse

Why? I didn't. Earth the socket yes, but why the actual greenhouse?

'cos it's structural metal. Unipotential bonding?

It should be earthed

Neither did we. Also ally g'house. And, ours was installed by a registered Sparks so we assume he did all that was required.

Well I would or it could be tingle time.

Brian

I'd bond them together. We had one which had a plastic base and gave small tingles occasionally. Brian

Not quite sure what you mean...

If you mean you should export the house earth and attach it to the greenhouse framework, then generally I would say no that's not a good idea.

The difficulty with greenhouses is *avoiding* an earth reference to its structure, since its typically sat on damp ground! This complicates matters since if you have TN-S earthing and export that, you don't know whether the local earth is at the same potential as the exported one (which may be connected to real earth some significant distance from the GH).

If the house is TN-C-S, then you would need to export the whole equipotential zone and make the GH part of it including any extraneous metal work. However since you can't guarantee that there is no access to an independent earth, this is also a poor choice.

The safest solution it to isolate the earth of the supply at the greenhouse end (i.e. leave the SWA protected by the exported earth as far as the GH. The make the GH a TT zone in its own right.

Have a read through:

for a fuller explanation