TNS, TT SYSTEM

[Bradley6969]

Got a question (this job is done), Mains is TNS, now there is an SWA from mains that feeds a panel, now I’ve tested this site a few times and readings vary for some reason, now to be safe feeding a new panel which will be outside then to some outdoor sockets, the panel (with upfront RCD) is fine Ze of 0.45 which is good, but at the boxes was in the 3.35 ohm range, now I’d already glanded the SWA in and used the earth so all I did was added a earth rod for additional protection, any one could explain why my readings was higher?

 

[buzzlightyear]

Loose gland and why did you put in earth splke knowing its a tns

 

[Bradley6969]

Loose earth some where like gland .

I did speak to DNO about earth as owner said last spark rang them as supply was unstable over 0.8 ohms and all they said was add a rod for additional protection and RCD the circuit
[automerge]1569171497[/automerge]
So would you put TT disconnection times or TNS?

 

[westward10]

Is this the caravan park?

 

[Bradley6969]

Is this the caravan park?

No it’s industrial site with sockets for catering equipment

 

[buzzlightyear]

If the readings are well unstable then the DNo need to sort it out considering it a TNS. Is it. Three phase or is it a guessing game for us .voltages should be constant not over the place .or im i reading this post wrong .

 

[westward10]

What do you mean by at the boxes, where you have the higher Zs.

 

[Bradley6969]

What do you mean by at the boxes, where you have the higher Zs.

Yes there higher at boxes

 

[buzzlightyear]

Yes there higher at boxes

either you have a bad gland or you are not testing it correct .

 

[westward10]

Yes there higher at boxes

What are the boxes.

 

[Strima]

Have you checked the circuits for high resistance/poor joints?

 

[ipf]

Boxes.....socket outlet points, presumably?
There are too many unknowns. How far are the cable runs, any variance in Ze at different points, size of cable, type and size of breaker, full test results, etc, etc? Did you test before TT?
If there is a genuine supply problem, don't let them fob you off with that TT crap.