old board earthed conduit system?

[jozza]

Hi all got a look at a friends db in his old flat at first it appeared to have no earths at all but I wonder if it is using the conduit as earth. No green/yellow in board or circuits.

Is there any way of identifying this.

thanks.

 

[Bigboy247]

Check behind the 1st fuse on the left looks like earth teminal, earth might come from behind the board.

 

[jase]

what about t the service head? is there an met? do a continuity

 

[jozza]

The met is down in riser under stair well has suppliers in and main gas and water

 

[Spudnik]

Ze at the CU will tell you if there is an earth present.

 

[jozza]

Is that the earth terminal behind left fues? old ceramic MEM db

 

[malcolmsanford]

The chances are that the original installation relied on the conduit for the earth, and at the intake the conduit was earthed someone. You

You will need to a do Zdb at the flats board to make sure you have that earth still. If there is then you should go around the flat really with a wander lead and make sure that your getting continuity at the accessories.

 

[jozza]

thanks sounds like a way forwards. I think i will have to change bd for new one no rcd on anything by the looks of it.Can I still use conduit for earth on new db?

 

[Engineer54]

Just been having a closer look at the OP's photo's. Now i maybe miss-taken here, but it sure looks to me, like they have run the supply tails through separate metallic conduits!!!! (last photo!!)

So apart from the earthing situation, you now have another problem to sort out, ...If i'm right of course, and if it's physically possible to sort out!!!!

I can think of one way, but it wouldn't look particularly pretty to the professional eye!! ...haha!!

 

[bozobro0]

If i were to do a board change i would place a banjo around one of the conduit bushes and crimp an earth cable to that.I would also cover the circuits with RCD protection.First off tho i would verify that i had a good earth through the conduit,If not look at the possibility of running a seperate cpc through the tubework if not to difficult.
Engineer54-I agree it is difficult to see if the main phase cable is run in a seperate tube,or if it is hidden behind the neutral.As for your last suggestion,LMFAO.

 

[nickblake]

What i think you need to do is a PIR on the installation just to ensure there are not underlying problems changing the CU may cause allsorts of problems , what is the extent of the conduit if it goes round the complete install then they are ok as long as the Zs resaults are satisfactory the main problem using the conduit as the cpc is if any part of the install has been altered then the conduit may have been cut or altered and the continuity lost then parts of the install may have no earths,cpc's could be installed but would be easier to rewire

 

[Engineer54]

I think there's little doubt that this installation is indeed a fully conduited system. If it was installed correctly, and i have no doubt about the quality of the conduits installation, then probably all that may be required prior to testing is that all the brass bushes be given a tighten.

The only worrying thing i can think of, is that if installed in black conduit, there maybe degradation if any dampness has been present. If there is degradation, depending on the extent, it maybe impossible to rewire or pull in cpc's. But to be honest, i think that won't be the case, and all is well....