Testing earth electrodes

[hartdev@hotmail.com]

Hey guys,

Anyone have any advice on testing earth electrodes in a place where there is just concrete/tar/unremovable paving?

I have read somewhere about wet clothes wrapped around the test spikes but I'm sure you wise guys have some great ideas.

Thanks

[AndyD]

I'd only do the 'lazy' method as it's called of just laying the spikes in a wet cloth or lappie on the concrete if the tester you're using has a warning system for open circuit spikes. I'd also only do it with concrete, not tarred areas because tar won't give you the conductivity (Ufer effect) required.

Bottom line is I've never had to make an Ra test that way, I've always drilled sneaky 5mm holes into the carpark surface, poured a cup of water into the hole and used improvised spikes made from M5 stainless thread rod pushed into the loose substrate under the solid surface. The holes it leaves are unnoticable to the point I've returned to do the same test 5 years later and could hell find the holes I'd drilled the previous time. I've even drilled in the grouted space between tiles and filled the small holes with a bit of grout afterwards.

There's also 'spikeless' earth testers like the Fluke 1630 which look like a clamp meter, they're damned expensive (about R40k and upwards) but you might be lucky and find somewhere that rents them by the day. If you decide to buy one let me know, I'll give you a call if I ever need need to rent one.

[hartdev@hotmail.com]

Andy that was just the kind if advice I was hoping for thanks.
I will try your method of 5mm thread bar.
I have a major tech MT330, I will check on the open spike specs for interest sake .
Will let you know if I ever decide to buy the fluke and skip my son's school fees for a year lol

All the best