Earth Rod Resistance (ARW?)

[Andy Wade]

Ineffective earthing was very common, right into the 1950s and 1960s.

[Tim Watts]

I though ELCBs were much older than that - or were they not mandated?

[Dave Liquorice]

Only if the voltage remains unchanged and as leakage sources are likely to be HiZ once you start to take any current the voltage drops. I've been to this location many times and never felt a "tingle" even when deliberately touching chassis and struture.

Donno where the intake is but it'll be 50 yds minimum. Bear in mind that these trucks and generators visit loads of similar places and its just this one location that gives problems. Also all the audio is balanced so the hum signal is big enough to get past the common mode rejection.

Not currently due to go back but next time I'll take a mulimeter if the company who deals with the permenant instalations has got it sorted.

This is true but could be arranged, wrap steel work in gaffer/insulation tape but intermittent incidental connections that can occur. Say from a secondary means of support safety wire that are not so easy to police.

[...]

Ta, that makes sense rather than some how distributing a fault current back to the power stations. B-)

[Andy Wade]

The leakage sources may well be Hi-Z, but they're dumping current into a low impedance earth system. The mains earth system is likely to be, say, Donno where the intake is but it'll be 50 yds minimum.

And possibly in a locked room to which you can't obtain access. Can you get a good bond onto the steelwork anywhere?

Sure, so likely that the conditions are worse here. Mains earth voltage higher than usual above the local ground, etc. Take some voltage readings.

Quite, and if you can't isolate, then bond. In the end though these sorts or problems can usually be solved by sitting down and thinking about where unwanted current can flow.

[Vir Campestris]

Our last house was built in the 1980s and just had fuses. Cartridge ones, but still fuses.

I'd actually have preferred wire!

Andy

[Tim Watts]

The ELCB would have predated the RCD - and only relevant (to this discussion) if you had a TT earth system...

You could use either fuses or MCBs with an RCD (or ELCB) on a TT system

[ARW]

Why?

I would have said that you had a better install.

[Tough Guy no. 1265]

I have no such problem with my fusebox. And my earth is through the neutral to the substation.

[ARW]

Just off the A461 in Tipton.