Bit of advice please.

[hoppy]

I have been asked to price a job in a shop, board change and replace 4 class 1 light fittings!


However the sockets and lighting circuits are all wired stranded aluminium single core cables with no cpc's, however they are wired via galv conduit so obviously they get an earth from this!

i know this needs re-wiring, but same old story of not enough cash.

The cables are definitely tinned copper, they are 100% aluminium!

would you guys be happy changing the db if test results are satisfactory?
i would obviously state on eic that rewire is recommended!

Also would you be happy installing new class 1 lights with only the galv conduit as cpc, I suppose if the zs comply then this would be ok.

there are four 5 amp lighting circuits and four 15 amp socket circuits!

thanks

craig

 

[telectrix]

as longas the cables give satisfactory readings and the conduit is continuous and you get sensible R1+R2 continuity, then fine. a comment to replace aluminium cables on your cert.


edit: The cables are definitely tinned copper, they are 100% aluminium!

make your mind up. they are copper or aluminium . one or the other.

 

[Lucien Nunes]

stranded aluminium single core cables

I'm trying to remember whether I've ever seen any cables fitting this description. Aluminium T+E, solid core, and larger singles maybe stranded. But specifically small csa such as you would use on lighting e.g. 0.0015 / 0.002 sq. ins I don't think I've ever seen in stranded ali. Did you get any pics of the cable?

If the conduit is properly erected and intact then it's absolutely fine as the CPC and will give you much better Zs than a bit of 1mm. I'm not so keen on relying on huge long runs of steel conduit with dozens of poorly supported joints like you sometimes see snaking around architectural features, where the first person to lean a ladder on the conduit will leave a chunk of it swinging in the breeze.

 

[davesparks]

Use some barrier grease on the terminations and there shouldn't be a problem.

As far as using the conduit as cpc goes it's a bit of a non question isn't it? Conduit is a much better cpc than a thin bit if copper put inside it.

 

[hoppy]

Thanks for the replies!

tel, I meant they are not tinned copper, ha sorry typing to quick!

 

[hoppy]

Hi lucien

they are 100% stranded, could they be another type of metal like tin. I have a picture of the db with the cover off, on which you can see the neutrals but I don't know how to upload it from my phone.

 

[Lucien Nunes]

No, they will be ali or tinned copper. I'm not saying you're wrong, it's just that I've studied an awful lot of weird and wonderful vintage cables but never knowingly seen any like that. Cutting the end and looking at it is not infallible, as with tinned copper the very thin layer of tin that the cutters smear over the surface can make it look silvery right through. If in doubt I'd be comparing the surface lustre, hardness and perhaps doing a little flame test with my pocket gas torch. What sizes are they?

I do hope you manage to prove it one way or another, and if they are ali I would be grateful for a couple of pics of the install and anything to indicate the date. I would also be wary of the condition of the terminations, as I would expect ordinary screw terminals to be even less effective on stranded ali than on solid, due to the lack of continuity between strands caused by the oxide layer.

 

[Dave OCD]

I bet the conductors turn out to be tinned copper.