tips for making earth electrode

[Aidanktm]

dear electricians, I am going to install 2 earth electrodes for a block of 4 apartments. can you please give me some tips on how to drill the hole for it and what diameter and length the hole shall be . also if you know any other tips that might help my installation please let me know. some photos will be highly appreciated ???. thanks everyone and stay safe ????

 

[telectrix]

depends on where you are installing the rods.if it's soil, no drilling needed. if going through concrete first, drill a bit bigger than the size as the rod to allow for couplings.. SDS drill and a decent bit. once through the hard stuff, the rod will hammer in, home made tools to fit SDS on hammer only help. genreally a 5/8" rod assembly with couplers giving a total length of 10 ft. earth pits added once readings have been obtained.

 

[Marvo]

Are you going to hammer in two separate earth rods or are you going to couple them together to make one long rod?

I usually dig the first meter or as deep as possible by hand to avoid hitting other services like water pipes, drains, MV or LV cabling, comms/fibre cables, gas pipes etc. Then hammer in the first 3.6m rod using a slide hammer. Then fit a threaded coupling and the second rod on top. If the rod impedance test is bad I go with a third rod if possible or install a separate rod about 10-15 meters away and link the two using bare copper wire.

I prefer a slide hammer because you get a feel for what the ground and the rod is doing as you hammer it in. If the ground is too much gravel or rocks I resort to an SDS Max jack hammer with a rod driver.

Once the rod is in I fill the hole I first dug with Bentonite.
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I wouldn't normally drill a hole through concrete slab and hammer a rod in unless there's reliable and detailed 'as built' drawings available.

 

[R-fur]

If you cant get bentonite, cat litter works as well

 

[telectrix]

If you cant get bentonite, cat litter works as well

is that because the local cats will all come and pi$$ on it, keep it moist?

 

[stevels4]

is that because the local cats will all come and pi$$ on it, keep it moist?

Or you come back after it has rained to get a decent Ze reading ?

 

[Mike Johnson]

Any second rod should be at least the length of the first rod away from it, preferably two lengths, this is to prevent the second rod being inside the zone of influence of the first rod and giving a false resistance reading.

 

[Baddegg]

is that because the local cats will all come and pi$$ on it, keep it moist?

Bit off thread but that post jogged my memory of a mate of mine....who used to c&£p in his mums cats litter tray for a wind up......the poor woman never did work out how her little cat laid them that big! sorry op.....?, and sorry mods but it jogged my memory and made me laugh