No CPC on one of my lighting circuits - worth amending?

[JohnD]

Stuck in their ways.

In the same way you still find people who like to put sockets down by the floor.

Or insist you mustn't have a light switch in a bathroom. Or even in a toilet.

 

[JohnW2]

That is one of the so called regs that don’t make sense.

I agree. Given that 4mm² is way above what would be required as a CPC in a multicore cable in the great majority of circuits, I can but assume that the 'thinking' (if that's what one calls it) behind this reg presumably must relate to 'mechanical vulnerability', rathe than anything electrical. Mind you, it's worse than that because, even if 'mechanically protected', a 'separate CPC' has to be at least 2.5mm² !

I would happily ignore it and use 1.0 mm green/yellow wire. Much safer than no earth and just as safe as T& E.

We each know what we would personally do, but I would not (and don't think that anyone else should) suggest that anyone else should 'ignore the regulations' (even though they are 'non-mandatory')

 

[JohnW2]

In many cases, older electricians used to nip off the earthwire when using T&E cable in the 1960's and even 1970's. A source of great annoyance to those who came after.

Why would they do that ‽

Maybe because many of the accessories of the day had no provision for 'safe parking' of a CPC, and they didn't want to leave a bare earthed conductor 'loose' within the accessory, with the potential risk of it coming into contact with something 'live'? ... but, yes, very annoying for those who have 'followed'.

Kind Regards, John

 

[elsmandino]

Cheers everyone - really helpful advice. I genuinely find all this really interesting.

BTW brits call it "earth", yanks call it "ground", if you see the word "ground" you are probablly reading an american site. Wiring practices are very different on the two sides of the pond.

Can't believe I said that - indeed I have been watching lots of US videos and it seems to have rubbed off a bit.

I popped into the loft, to have a nose around, and the cable is (thankfully) not rubber. I am pretty sure that my home doesn't have any of that but great to aware, just in case I do find any.

I was going to just change the switches and light fittings, but then one things occurred to me - at the moment, the wires are just sitting on top of my loft joists as I only have 100mm of insulation (where I have any at all). If I raise the insulation to 270mm, there is the possibility that there is not enough slack in some of the cables to lie it on top.

That being the case, I might have to swap out a couple of the cables for a longer size (though, as mentioned previously, I should swap in the same number of cores so as to avoid any confusion for any subsequent people working on it).

One great tip, that someone gave me on a separate thread, is to cut a hole in the loft boards over any junction boxes (with room to fit in a hand) as this allows easy access to the wiring without pulling up all the loftboards.

Regarding the new switches - sorry if this is a silly thing to ask but how can you be absolutely sure that a device is double insulated before buying it? I have had a look at switches and pendant light fittings and it just does not seem to say "Class 2" or "Double Insulated" anywhere. Is it implied that anything plastic (and from a reputable seller) is automatically doubly insulated?

 

[ETAF]

that a device is double insulated before buying it?

the icon is a box in a box

TLC Electrical Supplies

TLC Electrical Supplies - fast online sales of electrical cable, wiring accessories, lighting, heating and security equipment

www.tlc-direct.co.uk

as to

absolutely sure

cant say

With my installation the electrician used a tool which cut a circle in the flooring in the loft with a ridge and dropped plastic covers over - so its still flush , but i can access various sections easy
not sure what the tool is called though - i thought i saw it in toolstation / wickes recently

 

[EFLImpudence]

Lighting cables will be fine under insulation. With 6A circuits, they are hugely oversized and can cope with the maximum 50% derating.

 

[DetlefSchmitz]

I'm pretty sure that this symbol doesn't apply to light switches, and won't appear on them. If it's plastic it will be OK.

 

[pcaouolte]

With my installation the electrician used a tool which cut a circle in the flooring in the loft with a ridge and dropped plastic covers over - so its still flush , but i can access various sections easy
not sure what the tool is called though - i thought i saw it in toolstation / wickes recently

Armeg solid board cutter.

This is a cheaper version: https://www.screwfix.com/p/erbauer-wood-cutter-111mm/80049

These are the covers: https://www.screwfix.com/p/armeg-sbc-cover-111mm/10648

 

[sparkwright]

If it is a bungalow, and the wiring is accessible, in the loft, it should be easy to rewire.

Wiring of that age was usually done properly, with conduit in the walls for the switch drops, and also cables in brick cavities - so replacing the wiring could be very easy.

 

[ETAF]

Armeg solid board cutter.

Thanks @pcaouolte

yep, i thought i had seen them somewhere - so screwfix -
Not cheap then
he used quite a few around the loft flooring

 

[pcaouolte]

Thanks @pcaouolte

yep, i thought i had seen them somewhere - so screwfix -
Not cheap then
he used quite a few around the loft flooring

Not cheap but save a lot of labour costs as quick to use. There are 2 sizes 111mm and 127mm. The 127mm covers tend to be a bit cheaper but the proper Armeg cutter for them is about £90

 

[JohnW2]

If it is a bungalow, and the wiring is accessible, in the loft, it should be easy to rewire.

Indeed, at least some of it.

Wiring of that age was usually done properly, with conduit in the walls for the switch drops, and also cables in brick cavities - so replacing the wiring could be very easy.

Again true, but some eyebrows (including those of the regs) might be raised if one ('easily') replaced cables within wall cavities with new cables within wall cavities, mightn't they?

Kind Regards, John

 

[sparkwright]

Indeed, at least some of it.

Again true, but some eyebrows (including those of the regs) might be raised if one ('easily') replaced cables within wall cavities with new cables within wall cavities, mightn't they?

Kind Regards, John

Maybe, but you can't worry about everything.

What are the current rules about cables in cavities?

 

[securespark]

Why would they do that ‽

Because they were old school, used to a two-wire system for lighting and couldn't be arsed dragging themselves into the latter half of the 20th C?

 

[sparkwright]

.