Quick help please back me up

[domestic spark]

Working on a TT installation used to tns and tncs supply types is it ok to use a metal clad board?

And also reading of ZE at origin is 0.45ohms which is good as way under 200ohms
Pefc 515a

I remember reading that you no longer have to have 100ma on main switch if all your circuits are protected by 30ma rcds.

I plan to fit metal clad dual rcd board

No reg bOoks to hand thanks I'n advance

 

[johnboy6083]

no metal clad board, unless your tails are protected by an RCD. Use plastic board, and your right, a 30mARCD is all that is needed.

imagine a situation where the tails are damaged, and your metal clad board becomes live. the tails are not protected by the RCD inside. that board could remain live indefinately due to the high impedanc on the earth not allowing enough fault current to blow the cutout fuses.

 

[domestic spark]

Cables come I'n overhead through loft and straight down do DB where meter board is a 6mm green earth appears from it disconnected this from MET and achieved a reading of 0.45 ZE there was 2 however one went to gas so chopped and replaced with 10 water comes up I'n kitchen and appears not to be bonded.

I cannot seem to find an earth rod anywhere ??

 

[telectrix]

could be your getting your readings from gas/water. you've really got to disconnect these and find the rod. as johnboy says, use a plastic CU, not metal unless you RCD your incoming tails.

 

[IQ Electrical]

Cables come I'n overhead through loft and straight down do DB where meter board is a 6mm green earth appears from it disconnected this from MET and achieved a reading of 0.45 ZE there was 2 however one went to gas so chopped and replaced with 10 water comes up I'n kitchen and appears not to be bonded.

I cannot seem to find an earth rod anywhere ??

You are normally very lucky to get 45 Ω on an earth electrode, never mind 0.45 Ω so it would seem that you're measuring something other than the electrode.

 

[telectrix]

could be TN-S --earthed to incoming cable sheath wher he can't see it. i'd be wary of a reading that low on a TT

 

[domestic spark]

I'll have to put a rod I'n then or ring dno and enquire if supply can be tncs pme. Is there Anyway I can test existing 6 mm green and find out if it's linked to anything? Looked upstairs and goes off through joist dunno where then looked around house at pipework/ stopcocks no sign of other end, Or clamps? I'n no rod anywhere ?? Sorry guys suggestions please ?

 

[telectrix]

hammer and crowbar.

 

[domestic spark]

hammer and crowbar.

Really I can't mate thick fitted carpets furniture etc, any way of confirming by test? There is no sign of that wire going out from house though walked around it 4 times.

 

[domestic spark]

could be TN-S --earthed to incoming cable sheath wher he can't see it. i'd be wary of a reading that low on a TT

two seperate cables come into property side by side, then fed through in white tube, down airing cupboard then through downstairs ceiling to meter. brown in colour with red sleeve, and N with black sleeve about 2" long.

im gunna have to put a rod in, high chances it is just a reading from pipework??

or any other suggestions??

as i run 10mm earth bond for water and gas, thought id see what reading was off that alone, disconnected from my new CU and achieved a reading of 0.30 ohms.