Earthing System

[dziqs]

Hi guys

Would that be a TNS system or TT?

Cheers

 

[telectrix]

depends on what the other end of that EC is connected to at t'other end of the duct.

 

[Karin]

how have you managed to rule out TN-C-S?

 

[spary]

looks like TN-C-S to me, although I've been known to be wrong.

 

[dziqs]

True it could be TNCS...
Unfortunately I won't be able to find out where the other end goes..
Ze reading is 0.19 Ohms, isn't very low as for tt system?

 

[Wilko]

True it could be TNCS...
Unfortunately I won't be able to find out where the other end goes..
Ze reading is 0.19 Ohms, isn't very low as for tt system?

It's not likely to be TT at 0.19 Ohms (never seen that low a value). If the L-N impedance is higher than Ze then I'm voting with Karin and Spary for TNCS. Is there a prize for the correct answer ?

 

[dziqs]

Well it's 0.16 Ohms.. What now?
A lollypop as a reward hehe
Is it true that if impedance between L-E is the same as between L-N then it's a TNCS?

 

[Gnasher]

TN-C-S with an additional earth rod.

Is it within a building or a remote cabinet. What environment is it located.

 

[westward10]

There used to be a requirement to stake PME systems to keep the resistance to earth below 20 ohms maybe that is what it is?

 

[dziqs]

It's located on the ground floor of the block in the locked room

 

[Gnasher]

Possibility it could be connected to the reinforcement steel but not sure.

Best contact DNO and enquirer.

 

[mhar]

If it is in a block then that earthing stud could well be doubling up as the Building Network Operators earth marshalling point and the conductor rising from the duct could be a main protective bond of the incoming water / gas / steel (although this does look potentially a bit undersized).
I would be contacting the DNO to ask what the earthing system is and what the size of the supply is so that you are able to confirm adequacy of the bonding in relation to the supply neutral

 

[dziqs]

Thanks guys for all your help, much appreciated.
I phoned the ukpowernetworks (London area) and they said they don't have this information... something is not right.
I'll call them again on Tuesday.

Thanks again and enjoy your weekend!

 

[Knobhead]

It’s all covered in the UKPN online documentation if you care to look for it.

It’s glaringly obvious what the earthing arrangement is.

 

[mjb]

Looks like 95mm or 185mm cne cable. PME with an additional earth rod favored by IDNO's.