Suply Type ??

[T&Earth]

Hi Every One
Just need a bit of advice Please, what would you say the suply type is?? I cant fin a earth rod any where, customer says there isnt one Ze or Ra reading is 0.15 ohms pretty good for TT so I can only think its A TNCS but the earth is sperate??!!


Many Thanks

Any Help would be appricated (I'm stummped)

 

[truckster]

Could be a TNS. Where does that cable go that disappears out the bottm of the box?. Is it sweated onto the supply sheath behind the black cover?

 

[oxocube]

Looks like TNS.

 

[T&Earth]

Hi Guys

Thanks for your advice, the earth cable goes into the gound?
Many Thanks

 

[MarkieSparkie]

Most likely TN-S.
Your measured Zs is so low it's a most improbable Ra for TT.
It looks like the wrong head termination for TN-C-S, but measure PSCC and PEFC and if they're both the same you'll know it's actually TN-C-S and if different it's TN-S.

 

[Amp David]

If the earth goes into the ground then surely its TT. I would of thought that if it were TNS then the connection to the suppliy cable would of been made in the meter box.

Did you disconnect your main bond for the Ze. Only reason is on a CU swap that was TT with the bonds connected i had an RA of 0.19

 

[gnselectricals]

Is it an overhead supply ? Had one the other day was TNS but supplied with a seperate earth from the pole
Regards gram


Sent from my iPhone using Tapatalk

 

[Spudnik]

Do a Ze on supply line & neutral.

That will help rule out TNCS which im sure it isnt.

After that, its a process of elimination and investigation, but its unusual to have a lead incommer with a spike.

 

[rob121]

Is it a 16mm E/Conductor? Hard to see whether its a 10 or 16mm. Only reason I ask is it could be a bonding cable giving you a false reading to earth? Just throwing it out there, as it does seem strange how theres no clamp near the cut out.

 

[drew35]

What everyone else said, plus it looks like the job has been vomited in there at five to four on a Friday!!!

 

[T&Earth]

Hi Guys

Thanks very much for all your helpful comments. The reading for PSCC was 2.49 kA the PEFC was 1.41 kA there are no overhead cables.

Many Thanks

 

[T&Earth]

Hi Rob

The eath conductor seems bigger than 16mm when I offered up my sample 16mm, but I'm sure its not 25mm and as theres no inbetween size it must be 16mm??!!
Thanks for replying to my thread

 

[yellowvanman]

Tried asking the DNO?

 

[cakey]

http://www.electriciansforums.net/e...-forum/26217-what-earth-supply.html?highlight=

might be helpful

 

[JamesBrownLive]

As I'm still learning, can I just ask a couple of questions regarding this installation..

1. What is the purpose of the small black box right next to the service head? The one that looks like it is taking a feed from the live.
2. Why is there an earth cable going into the second meter?

Cheers

 

[truckster]

The little black box is a fuse for the time clock and the clock is earthed as its a class 1 piece of equipment. Its an old economy 7 arrangement

 

[tony2010]

Could it be a TT with the cable going down to a earth plate or a mat

 

[truckster]

It could be just a stripped piece of g/y going into the ground. We used to do that on the campsites for TT systems. Should be a min 25mm tho

 

[T&Earth]

Thanks ALL for replying will try and contact DNO but as its a holiday home will have to wait the owners are back again.


Many Thanks
T&E

 

[SPARTYKUS]

Another possibility is that it is a TT.

And the water mains is connected to next door.

And its bonded.

And they have TNC-S

mg_smile: