Earth electrode

[Maxxy]

Hi all. If an earth electrode has been fitted straight into the ground with no pit and cover, is it easy to retrofit these to bring it up to regs, or am i better off installing a new spike? Can i leave the old one in still without the pit and cover, if i install another properly, or should i remove it/disconnect it? Cheers

 

[RF Lighting]

What sort of ground is the spike into?

Can you not just disconnect the earth wire, fit the enclosure, and reconnect the earth wire?

You could bash the spike in a bit deeper if you need to dig out some of the ground to accomodate the enclosure / pit.

 

[Maxxy]

What sort of ground is the spike into?

Can you not just disconnect the earth wire, fit the enclosure, and reconnect the earth wire?

You could bash the spike in a bit deeper if you need to dig out some of the ground to accomodate the enclosure / pit.

Ive not fitted one before, so wasnt sure if the enclosure could be retrofitted. But as i might be doing some electrical work there i will first need to bring the earthing up to scratch, so thought id better look into it, to see what the options were

The spikes just into dusty ground (farm land, old barn kind of thing) so it shouldnt be a problem digging it in deeper.

Is the job of the enclosure to keep the joint watertight, or just for easy access if the cable needs changing or anything in the future?

 

[mike++]

i wonder if one of the electricians could enlighten me on the principle of the grounding spike? They confuse me - surely the type of soil, clay etc and the amount and salinity of the water in the ground will determine the impedance between the spike and the true proper earth point at the power source?

What ground conditions make the spike a reliable or unreliable earth?

 

[securespark]

In the worst case scenario, you cannot exceed 200 Ohms.

This means you need a good solid connection with damp ground. A rod in dry, rocky soil will not suffice.

 

[mike++]

In the worst case scenario, you cannot exceed 200 Ohms

Thanks!

But 200 ohms between the spike and WHAT? Where do you measure this impedance?

(sorry - not playing devils advocate, i really am interested!)

 

[Adam_151]

Two methods of testing, one involves two more spikes nearby and a special electrode tester to measure impedance to the earth as a whole (which is assumed to be of very little impedance, due to the thousands of parrallel paths that exist) Its the only way to do it when earthing down a generator in the middle of a field, etc.


If you are installing a TT system then you can use a loop tester as its the loop that you are really worried about, this takes into account the suppliers electrode as well (which can be upto 21ohms*)

*It also may have rotted off and you're the first to notice!

 

[mike++]

Great, thanks Adam!

 

[Chivers7]

http://www.rsc-northwest.ac.uk/Curr...llation/myweb3/earth_electrode_resistance.htm I suggest perhaps getting in an electrician to help you with this look at the link I searched on the web. You could buy a IEE GN3 or something similar to guide you http://www.amazon.co.uk/Testing-Electrical-Installations-practical-electricians/dp/2952413835
It needs to have ZE test and you don't normally "dig in" spikes as this will not give you a good Earth. You could also get a mesh type electrode as well

 

[jayc]

Working in Egypt earlier this year (I'm a set rigger) the local ground crew proceeded to earth our 3 phase supply in a giant plant pot telling us it was ok because "this is earth yes?" pointing at the soil!