Is this TN-C-S or TN-C, also earth bonding size.

mR__Slug · Oct 4, 2023

I've tried to understand one way or another but this seems to be connected to the DNO fuse/cutout, and then loops down (out of sight) and comes back up to connect to the outer sheath.

[ElectriciansForums.net] Is this TN-C-S or TN-C, also earth bonding size.

The bonding looks like 6mm^2. And the connection point looks like that's the max it will take. As I understand it, TN-C-S needs 10mm^2 so TN-S?

davesparks · Oct 4, 2023

It's impossible to tell from looking at it.

It would have originally been TNS and the original cutout has been replaced with that one.
But those cutouts have a removable N-E link, so it could still be TNS if the link has been removed or it may have been left in place to convert it to TNCS.

mR__Slug · Oct 4, 2023

Thanks, though not the answer i wanted

I had a man out to change the meter, should have asked him. If the DNO fuse was 1/4" to the right, he could have changed it. Got to sort out the door for clearance.

There are two issues here. First I need another bond to the gas. From the CU? Or split the CU wire and a terminal block for the additional gas bond. Then we have the size issue. My house is in the process of being renovated, so now would be a good time to pull a wire.

It's an Earth Loop Impedance Tester that'll allow me to measure and find out? Ze reading or or something can be used to work out what I have.

I want to update the CU to 18th with RCBOs at some point so hoped I could sort bonding first.