TT system help.

[ChrisElectrical88]

Hi, I have a lad working on a farm at the moment and he phoned me today panicking at a high ZE and PSC. 3.50ohms and 79kA. I asked him what system was in place and he said TN-S. I then told him to go earth rod hunting. Got a phone call back saying he couldn't find anything. I'm on a course this week so I don't have access to my regs etc. Are these good TT reading? (I'm not to familiar with TT so don't have much clue without my books) and should I tell him to open his eyes and go searching again? Or should I tell him to leave our new circuit switched off and go and investigate myself?

Sorry if its a stupid question.
cheers

 

[ChrisElectrical88]

I think I will tell him to leave it disconnected and get up there on Friday to check it out myself. It's RCD protected anyway due to it been a special location.

 

[JD6400]

If it is on a livestock holding , it would more than likely need to be TT anyway .

 

[stigwart]

If it is a TT system.

 

[shagbite]

doesn't make sense. if it's TN-S the Ze should be below 0.8. and to give a PSC of 79KA, it would be 0.003

sorry tel'.....i meant 0.079kA not 7.9kA.

 

[ChrisElectrical88]

If it is on a livestock holding , it would more than likely need to be TT anyway .

It is, cheers for the answers guys, ill let you know the outcome on Friday!

 

[Richard Burns]

I thought the 79 amps was okay for pefc Richard, but isn't that low for pscc?

I assume he means PEFC not PSCC.

 

[ChrisElectrical88]

Nipped up on my way through this morning. Never a TN-S in its life. TT with a 16 mm earth going out to a pit of 3 earth rods. God knows what he was thinking!

 

[shagbite]

well mate, you employ him. perhaps he needs a bit more tutoring before you send him out unsupervised.

 

[Amp David]

Blimey, wouldn't like to have him out on one of mine working by himself.

 

[ChrisElectrical88]

He's normally spot on to be fair to him. Don't know what happened with that one!

 

[telectrix]

brain fart. happens to us all.

 

[Knobhead]

He's normally spot on to be fair to him. Don't know what happened with that one!

So what happen next time he (you) has a brain fart?