ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades To: Pauluk

Yep, round my way the soil is rather sandy (well, the beach is only 200 ft. away!) so you can almost push a 4 ft. rod into the ground with your bare hands. Just don't expect a low resistance reading!

D'ya think the 4 foot earth rods got anything to do with the voltage here, not having 120 Volts? Or is it just that we rely on the meaty neutral more?

At least with RCDs you don't usually need to have 16amps or so flowing to earth/ground before something trips!

I think it's probably more the case of our earthing arrangements.

The only time an earth rod is required here is on a TT system, which will have an RCD, or in old installations a voltage ELCB or a current-operated ELCB of at worst about 500mA rating.

In the U.S., it's normal for all services to have a ground rod installed, despite the fact that they are equivalent to what in British terms would be a PME system.

I tend to introduce rods in new works where the PME supply is o/h and there's any risk that the neutral line could be broken - ie if the supply comes on a few spans through a wood or near trees ( which around here is usual!) before grounding.

I think that's an excellent idea, and I've sometimes wondered why BS7671 hasn't specified earth rods on PME systems as an extra precaution.

Paul, in the late eighties, a local NORWEB inspector told me I was being "over cautious and costing the customer more"...

What price a little extra safety eh?