Earthing problem

only if your local electrical code requires it. i would probably do it but there isn't really any shock potential so safety isn't an issue

-bob

All of the armoured cable connectors I have seen ground automatically, because there is a mechanical connection between the cable, the connector, and the service.

If you mean a separate ground wire, no not needed

I would, for many reasons. If you don't:

It is going to be at some voltage or another.

If the cable is damaged, it could come into contact with the supply and thus become live. Not a good idea.

If only the outer plastic sheath gets damaged and water gets in, it can have any old voltage induced in it, wrt ground and galvanic corrosion could eat the metal away in no time.

If some idiot later assumes it is earthed and connects to it as a safety earth without checking, boy are they going to be surprised if they get a fault.

The ends of the armoured strands need to have something done with them - just cutting them off and hoping they won't rub through the conductor insulation isn't a good plan. Apart from anything else, they are also there to take any tensile load the cable may have to take. Thus they normally get clamped to something and usually something metal - which will need to be earthed. So the armour will be too.

Thanks to all who replied I should have said that I have a metal junction box at present where the cable armour is earthed but I am proposing to change this to a plastic junction box, and there will be no earth available for the armour. Can I safely do this? Blair

Why not use a locknut for the cable gland that has a terminal for an earth or an earthing tab that goes under the gland locknut?

Thanks. To make sure what you are proposing is this correct Wire the earth tab on the cable gland to the earth wire within the 3 core cable itself? Blair