Steel conduits acceptable for earthing in domestic property ?

[NEB Electrical]

Evening

Just been to quote for a consumer unit upgrade. Found that the board was from circa 1960 and wiring looked original also. No alterations have been made with exception of a few faceplates renewed in the kitchen. Red and black single cores going into an adaptable box at the back and then down the relevant conduits. No CPC's for any circuit. The only thing providing an earth is the conduits themselves.

My question is does this provide an adequate earth and would this be deemed acceptable once the new 18th edition unit is installed ?

I am of the opinion that it does not as there is technically only one earth point at the main board and if that were to fail, nothing in the house would be earthed, there is also no guarantee that the conduit system is 100% complete, although a long lead test could verify continuity ?

Any advice/opinions welcome.

Thanks in advance.

Nick
NEB Electrical Ltd

 

[ipf]

I test at each point and check condition of the backbox - which in one case revealed severe corrosion problems. It’s this arrangement that reminds us the purpose of the earthing lug in the backbox was to provide the earth to the socket - not like we do today with T&E and bond to it.

We're earthing the backbox not bonding it.

 

[l4urence]

We're earthing the backbox not bonding it.

Correct. My mistake, well spotted. I think I was getting to direction and went off at a tangent. With conduit we take the earth from the backbox with T&E we take an earth to it.

 

[littlespark]

Rewiring through the old conduits could be a problem.
Last one I worked on had a central box with pipes running out to all the sockets.
This box was just under the floorboards, and no access hatch. Had to cut one.

Give the customer the idea that decorating now would be wrong. Go for a rewire first. There won’t be enough sockets for them even changing all the singles to doubles.