TT Earth system tester

[Prytaneion]

I have to install a TT Earth Rod on a rural new installation. Can some kind sparky please point me in the direct of a hire company that will hire out a tester? My old megger 1502 won't do this and as there is no power on site at the moment, I need a battery powered tester for Ze.

 

[Nigel]

If you mean Ra then this mob does them:

Megger DET4TD2 - Express Instrument Hire - http://expresshire.net/product/electrical-test/earth-tester/megger-det4td2/

 

[rolyberkin]

Is there not another local sparky who will tip out to do it for you for a few beer tokens? I can be bought for a couple of decent bottles of red but not as far away as Bognor!

 

[Fitzy]

The kewtech KT65 does earth rod testing, check if any of your mates have one of these MFT.

 

[Prytaneion]

I'll ask around but since forced retirement through ill health, I've lost touch with a lot of my mates in any case. the KT65 is a bit up market for them!!

 

[Prytaneion]

Hi Roly - The job is a rural site near Bath so travel is a problem from here. I might just bite the bullet and hit ebay...

 

[Flanders]

Just to confirm you will nead an Ra tester not a ze tester as there is no Ze on a TT system ☺

 

[Prytaneion]

Hi Flanders (Whoo-Hoo) - Ra it is - my mistake... :0)

 

[Nigel]

Just to confirm you will nead an Ra tester not a ze tester as there is no Ze on a TT system ☺

Yes there is.

 

[rolyberkin]

I had a similar job and bought a megger det3tc from ebay a while back and used it once! However I have got another job coming up in 2019 where I will use it again!

 

[Prytaneion]

Hi Roly, yes mate, I have a similar problem but today I have found a local sparks who will test the earth rod (s) actually there are two 2M rods - for fifty quid so I'll probably go with this option. TT systems are a pain in the butt, however, because they are what they are, it's imperative to get it right. Thanks for the chat though...

 

[Flanders]

Yes there is.

I have always thought Ze was the external earth loop resistance back to the transformer if there is no supply earth how do you get a Ze reading , or am I missing something ?

 

[Prytaneion]

The loop back to the star point on the transformer is through an earthing rod or rods. About 2 metres worth of copper beaten into the ground or tape etc.

 

[Prytaneion]

See the readings here: MAXIMUM Ze at origins of TT, TN-S & TNC-S, - https://www.electriciansforums.co.uk/threads/maximum-ze-at-origins-of-tt-tn-s-tnc-s.36256/

 

[Flanders]

The loop back to the star point on the transformer is through an earthing rod or rods. About 2 metres worth of copper beaten into the ground or tape etc.
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Thanks very much now it make sense .