Add earth terminal to a metal back box?

You could drill a hole in the side of the box and put in a nut and bolt, or, especially if it's buried flush, drill the back and use a self-tapper.

Chris

Drill through the side and put a bolt through.

Yes, as you say, thanks for the idea. If there is nothing special made for this job,I was wondering about using one of the unused lugs; there is a threaded hole there waiting to be used.

Anode

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Anode" saying something like:

Nothing to stop you doing that, if the lug isn't floating.

If you've got a pop riveter, fix a tail of CPC under a pop rivet with washer.

Thank you all for the ideas, I'll look at the box in question and then decide which method to go for.

Anode.

Just run a CPC from the earth connector block to a blue crimp ring and either use a pop rivet or a self-tapping machine screw with a washer to fix the crimp ring to the back-box. If you're using a pop-rivet, you might want to sandwich a star washer between the lug and the rivet to make sure you get a tight connection.

Crimp an eye terminal on the end of a wire, and screw to the backbox with one of these:

secured to

condition.

Looks more professional if you crimp a suitable sized lug to the cpc then pop rivet the lug.

AWEM

Extra crimps just mean possible extra problems.