No earth on ring main.

[oldtimer]

Oh and the reason I discovered there is no earth in the ring main is because I intend to run a 13 amp fuss spur for the underfloor heating for the bathroom off the ring main so I had to take a look at the socket on the landing which turned out to be in a bit of a state. I can run a radial from a spare mcb to power the stuff in the bathroom if I have to and I can ensure my work is earthed and safe but I am simply trying to find out what advise you guys would give about the lack of earth in the ring main as I don't want be accused of scare mongering by suggesting a rewire if there is another solution.

Well you will be scaremongering remember you cannot backdate the regs when these sockets were installed they complied to to the then regulations so if they pass IR Zs tests its good to go as for taking a spur from it yet again if it passes it IR Zs test then its good to go.

 

[charliewilde]

test for zs would have been a good start

What could be the very first thing to test? The ZS or the earth at the socket?

 

[oldtimer]

Where these systems can fail is if a plastic CU is fitted and the continuity between earth and the conduit is not there

 

[benji]

never seen a house done with screwed conduit ie. couplings & bushes ect. did a lot in 60s with split conduit with rubber gromets on the ends so i doubt if you could rely on conduit for good earth

 

[trev]

Guys, thanks for some of your replies. My question is.. If there is no earth on the ring main and it turns out not to be in earthed conduit which I don't think it is, do I recommend a rewire or is there any other option? And as far as diving in first without testing that's not the case. I think you find we inspect first then test which is exactly what I'm doing. The first fix in the bathroom is being installed and is dead until connected up which will be tested first of course. As far as class 2 sockets you know what I meant plastic not metal. And I connected the cpc from the spur to the earth terminal but like I said it doesn't look like an earth is going back so makes no difference at the moment. Pleas guys if your not going to reply with any helpful answers don't bother. Thank you.

Clark, there's a lot goes on here which is like site cabin humour. I know you can't tell people's inflection from the written word but the vast majority of it is just good natured ribbing

 

[Engineer54]

never seen a house done with screwed conduit ie. couplings & bushes ect. did a lot in 60s with split conduit with rubber gromets on the ends so i doubt if you could rely on conduit for good earth

You'll be surprised to learn that a good many older houses were fully conduited throughout then!! lol!! Even more so, blocks of flats, that when you think about it, makes a lot of sense being as they were primarily concrete floored and ceilings!! Some also being fully wired in MICC cable!!

 

[Atelcom]

but the vast majority of it is just good natured ribbing

Is that the same thing as on those condom thingy's

Ok I've already got me coat........!

 

[KAS1]

A lot of the old police houses (when there used to be one every couple of streets apart on estates) were done in conduit

never seen a house done with screwed conduit ie. couplings & bushes ect. did a lot in 60s with split conduit with rubber gromets on the ends so i doubt if you could rely on conduit for good earth

 

[Edd]

Check by doing an R2 reading, a ELI reading can give a red herring, Ive had decent readings testing Zs on old conduit systems in pre fab buildings, but complete open circuit at the low voltage of an R2 test. damp rusty concrete does conduct at 230V but no so well at 12v

 

[ste77]

test for zs would have been a good start

If hes unsure of there being an earth in the circuit, i wouldnt be carrying out a Zs test, earth continuity check would be my preference, injecting 25A into a circuit with no earth is dangerous.

 

[Engineer54]

If hes unsure of there being an earth in the circuit, i wouldnt be carrying out a Zs test, earth continuity check would be my preference, injecting 25A into a circuit with no earth is dangerous.

Can you explain that one to me??

 

[KAS1]

I think he means if his conduit is not earthed he'll be applying 240v to the conduit when he preforms his test and if someone touches the conduit at the same time, they will in effect make the circuit to earth causing a current to flow through their body to earth. I think lol

 

[telectrix]

and me. if there is no cpc, there will be no current flow L-E, so 25A is irrelevant.

 

[telectrix]

I think he means if his conduit is not earthed he'll be applying 240v to the conduit when he preforms his test and if someone touches the conduit at the same time, they will in effect make the circuit to earth causing a current to flow through their body to earth. I think lol

don't think my tester pushes out 240V on a Zs test. :shout:

 

[KAS1]

He could be testing at the back of the socket with the test leads connected to L N and crocodile clip on the metal back box

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true my mistake