Hi gents i live in a 1960 3 bed semi, the lighting cable is the original cable black and red no earth grey plastic sleeve. Is it possible to run separate earth cables to all the existing metal light fittings and use plastic light switches and boxes,or do i need to replace the old cable.Also is there any truth about cable breaking down over the years, ps whats the going rate for a spark these days
No earth
- Thread starter lanber
- Start date
Sponsored Links
You ideally need it rewired in twin and earth to use metal class 1 fittings. It is possible to run an additional earth but it needs to be in a minimum of 4mm earth cable which is awkward to do.
On the other hand, it is possible to buy class 2 metal fittings which can be used on your system. Class 2 or double insulated are marked with a square in a square symbol.
As for prices, can't see it so can't quote it, ask your friends and relatives for recommendations. Also ensure the spark is a member of a competent person scheme such as the NICEIC Domestic Installer, Napit, elecsa etc.
http://www.competentperson.co.uk/ (though the search facility is a bit poo, I have emailed ECA and was passed to DCLG whom I have asked nicely to change it)
On the other hand, it is possible to buy class 2 metal fittings which can be used on your system. Class 2 or double insulated are marked with a square in a square symbol.
As for prices, can't see it so can't quote it, ask your friends and relatives for recommendations. Also ensure the spark is a member of a competent person scheme such as the NICEIC Domestic Installer, Napit, elecsa etc.
http://www.competentperson.co.uk/ (though the search facility is a bit poo, I have emailed ECA and was passed to DCLG whom I have asked nicely to change it)
Whilst I certainly agree that it should really all be rewired with T&E, if one did decide to run a separate CPC, why do you say it needs to be a minimum of 4mm²? It's not supplementary bonding, it's a CPC, and even 1.5mm T&E only has a 1mm² CPC.
Kind Regards, John.
Yes - but by the time you have done this, you could just as easily have replaced the old cables.
Like everything else, the cable insulation deteriorates over time. How quickly this occurs mainly depends on what the insulation is made of.
If PVC / plastic, then it is probably not falling apart just yet.
If rubber, then it is already decades past its expected lifespan.
Either way, 50 year old wiring is overdue for replacement.
Other factors such as overloading the cable, installation in high temperature areas such as lofts, exposure to UV light (sunlight) and contact with materials such as expanded polystyrene will all cause the cable to deteriorate much more quickly.
Sponsored Links
P
Paul_C
Probably thinking of the rule in "the book" which sets the minimum size of a single unsheathed conductor run outside conduit or trunking, for mechanical protection rather than for electrical reasons as such.
Ah, yes, we've been through that one before. It's 543.1.1. As you say, 'if it's not part of a cable' it needs to be 4mm² without mechanical protection (2.5mm² with protection), just as for supplementary bonding.
However, as we discussed before, what is this 'if it's not part of a cable'? What is a cable? Part II of the regs doesn't give a definition, yet we have Tables, such as 4D1A, which give characteristics of 'single core insulated cables, with or without sheath'. That bit of BS7671 therefore regards a single-insulated G/Y as being 'a cable' !!
I suppose we can agree that what they probably meant to say was 'if it's not part of a multicore cable ....' - but they didn't, so I'm not sure where that theoretically leaves us
Whatever, as others have pointed out, I think we can agree that by the time one has run G/Y (of whatever CSA) alongside all the wiring of a lighting circuit, it would have been both easier and cheaper to replace it all with T&E.
Kind Regards, John.
Waste of time running separate earths, more practical to rewire completely.
Will be easier running a new twin and earth cable in an old switch conduit than trying to draw in a separate earth wire.
Should be very little damage if you get an experienced electrician.
Will be easier running a new twin and earth cable in an old switch conduit than trying to draw in a separate earth wire.
Should be very little damage if you get an experienced electrician.
As I said, I agree.
Is that a hypothetical comment? I don't think were talking about conduit, are we?
Kind Regards, John.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
