Metal comduit as cpc

[ryan24]

Hi all.

whats people's thoughts on having class 1 switches and fittings on an installation that is wired in old imperial conduit acting as the sole cpc? If there's a fly-lead from switch to back box surely this will be fine? Getting a lot of mixed anwsers on this some saying no good others saying perfectly fine? I personally think it's not a problem as conduit can be the best cpc you get. Any one else dealt with this? Thanks

 

[Sintra]

Absolutely fine so long as continuity is maintained.

 

[Deleted member 26818]

It's generally frowned on nowadays.
In an existing installation, in good repair, and it all checks out continuity wise, then it's fine.

 

[Octopus]

If you are concerned about the continuity, use your wander lead to do an R2 test to each point

 

[davesparks]

The regulations say it is fine, the guidance note pretty much says that running a seperate cpc inside steel conduit is pointless.

 

[Noob2013]

The whole of the hospital I have worked in uses steel conduit as an earth and the test results have all been very good.

 

[Clive P]

Hi,

Half of the buildings in this country are wired like that, perfectly acceptable.

Regards.

 

[netblindpaul]

It is perfectly fine.

It is frowned upon in certain circles, and by certain organisations, and with good reason.
The reason however is very sad.
It is frowned upon as the designers who have often little or no control over how the installation is constructed, are unable to rely on the competence of the installer to get the conduit correctly installed to provide an adequate cpc. Nothing more than that. Hence they add a secondary cpc within the containment in an attempt to ensure that there is at least one functional cpc.
Same reason that using the SWA has fallen from favour as a cpc.
It is simply that the designers cannot rely on the installer to do the job correctly so they design in some redundant safety, by insisting on additional cpc, either within the SWA or additional to.

Simply another reflection on the poor state of the competence in the installation operatives in the industry.

Note terms...

 

[Deleted member 9648]

Couldnt agree more with post #8.....would add that the dismal quality of steel conduit and accessories these days doesnt help.

 

[Noob2013]

It doesn't help that the new AM2 doesn't cover conduit. It's going down the domestic route so less and less electricians are competent with conduit!!

 

[ipf]

Couldnt agree more with post #8.....would add that the dismal quality of steel conduit and accessories these days doesnt help.

Very true, but a half decent spark should be able to sort it.

 

[ipf]

It doesn't help that the new AM2 doesn't cover conduit. It's going down the domestic route so less and less electricians are competent with conduit!!

Too true!!

 

[7029 dave]

Too true!!

View attachment 27412

No saddles, terrible.

 

[Knobhead]

Just thinking back to my old foreman, he would have beaten me around the head with a large and heavy blunt instrument for wasting time and money with an earth in conduit.

PS.We didn’t have CPC’s back then!

 

[jay sean]

I worked for a company and we worked for John Lewis, the spec was no earth wires.
No this was not in the 1960s but in 2000 in London near brands hatch.

The electrician who I worked with and was my 'mentor' said that it would have to be 'pressure tested'.
So even 'now' you do not need earth wires.