High Ze

[ml1936]

External Loop Impedance is 53ohms, so obviously circuit loop impedance is high as well. Is making circuits RCD protected ok, or should supply company be rectifying Ze? It's a TN-S system

 

[industryspark]

get on the phone to the supply company....thats way high. think there maximum qouted is 0.8 ohms so to be fifty times that, there is obviously something wrong.

without insulting your inteligence are you sure its TNS?

 

[ml1936]

Yeah Defo TNS, earth took from armoured supply cable. Thought loop meter had been broken, but tested ok on all other jobs since.

 

[industryspark]

strange, the circuit impedances must be well well out then.

is there rcd protection on any of the circuits curently?

whats the ze with the gas/water bonding in place out of interest?

 

[DESL]

Make sure you ring the DNO emergency number as this is a major fault and they should deal with it within 24 hrs

 

[ml1936]

No RCD protection on any of the circuits! Already told them there should be on sockets anyway. Thought putting RCD incomer might make up for high Ze, but needed to check with it being so umbelievably high!

 

[industryspark]

With no rcd protection at all this is a potentially very dangerous situation as im sure your aware!

rcd incomer would have been ok as a temp safety measure i suppose but im sure the REC will be out pronto if you ring and explain the problem, id make sure they are fully aware of the urgency

and id tell the occupants to give the shower a miss tonight!

 

[ml1936]

Funny you should mention shower, the power light on shower has just started flickering when turned on and the flow is stuttering and not warming up. Would this be the heater element? The Feed going to Shower is ok

 

[Jim2287]

TN-S can be changed to PME or not ?

 

[DESL]

[img=http://img392.imageshack.us/img392/4903/tnstopmend7.th.jpg]

Here's a TN-S to PME

 

[securespark]

You can't see what's happening inside the cut-out, though.

PME installs have a PME label, no?

 

[Adam_151]

TN-S can be changed to PME or not ?

It can if the network is suitable for TNC-S (plenty of neutral->physical earth) connections along the supply cable, however the electricity supply and continuity regulations 2002 require the DNO to earth a metal cable sheath, so if its rotted off in the street.... (however they might do what might have been done in the pic posted.... and earth the sheath from the house end with the TNC-S earth ?

 

[DESL]

Whether it has a label or not the Ze of the result was better than the 1.5ohms before I called the DNO to sort it!!!

 

[securespark]

Is it 0.35 or less?

 

[DESL]

0.08