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

[elsmandino]

Hi there.

I had a consumer unit put in and the electrician gave me the concerning news that one of the two lighting circuits had no cpc on it.

I have an old bungalow, that was extended at some point, and only the extended lighting system has cpc.

Most worrying is that there are a few metal light switches and fittings on the unprotected system, so I am going to immediately get rid of them.

Long term, is this something I should really worry about or will only using plastic switches/lights be enough?

If I sell the house, will this have to be remedied first?

Is the only way to remedy this adding all new wiring with a ground, back to the consumer unit?

This last point is only for my understanding and not something I would actually do - but, in principle, could you not switch two wire cable to three between all the light fittings on the old circuit. Then could you run an additional ground from any light on the newer system to the old and ultimately ground the old?

As I say, this is absolutely not something I would ever do. Am just trying to get a better understanding, generally, of electrical practices.

 

[EFLImpudence]

Most worrying is that there are a few metal light switches and fittings on the unprotected system, so I am going to immediately get rid of them.

Yes, that is what you should do.

Long term, is this something I should really worry about or will only using plastic switches/lights be enough?

I wouldn't worry about it. Plastic fittings and switches will be enough.

If I sell the house, will this have to be remedied first?

No.

Is the only way to remedy this adding all new wiring with a ground, back to the consumer unit?

Ideally - yes.

This last point is only for my understanding and not something I would actually do - but, in principle, could you not switch two wire cable to three between all the light fittings on the old circuit. Then could you run an additional ground from any light on the newer system to the old and ultimately ground the old?

You could do that.

You would also have to replace the switch cables if you want metal ones.


If you are happy with plastic fittings and switches then there is no point as you have nothing to which you would connect a CPC.

 

[jj4091]

Earthing the fittings will not earth the metal light switches & may cause confusion in future. Just swap the metal switches for plastic if you are concerned about safety

 

[JohnD]

As you have a bungalow, you could probably run an earth to the ceiling roses fairly easily.

Getting to the switches would be harder, unless you have conduit in the walls.

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.

 

[elsmandino]

Perfect - thanks very much for that.

Much appreciated.

I had completely forgotten about the switches themselves and, having checked, they are going to be a major pain.

Just going to stick with plastic only on the circuit.

 

[flameport]

Just going to stick with plastic only on the circuit.

That is an improvement over non-earthed metal switches, but it's not a real solution.

Circuits with no CPC haven't been permitted for almost 60 years. Any cabling of that age is life expired and should have been replaced long ago.

 

[elsmandino]

That is an improvement over non-earthed metal switches, but it's not a real solution.

Circuits with no CPC haven't been permitted for almost 60 years. Any cabling of that age is life expired and should have been replaced long ago.

That is a bit of a worry.

I am just about to completely redo my loft - i.e. put down 270mm insulation and interlocking loftboards, so now would seem to be the ideal time to change out any old wiring while I have access to it.

I centainly won't go anywhere near my consumer unit.

Is it permissible for me to change out all the wiring (if I can get to the light switches) but for the final connection between the consumer unit and the first junction, and get an electrician to do that last final bit?

 

[plugwash]

Long term, is this something I should really worry about or will only using plastic switches/lights be enough?

I wouldn't be too worried about a plastic lightswitch with no earth per-se.

What worries me more is that while there was a narrow window in the 1960s where plastic cables were in use and lighting circuits without an earth wire it's likely that you have old rubber cables (though I would have expected the electrician to flag this up when doing the CU change).

The trouble with old rubber is it often goes hard and crumbly. When in this state it can continue to insulate as long as it is not disturbed but if it is disturbed the insulation may fall apart. For this reason most electricians are very reluctant to do any work on rubber wiring other than ripping it out.

If I sell the house, will this have to be remedied first?

There is nothing forbidding selling a house with life-expired electrics, but a buyer (or their mortgage provider) may well treat them as something that needs to be rectified and adjust their offer accordingly.

This last point is only for my understanding and not something I would actually do - but, in principle, could you not switch two wire cable to three between all the light fittings on the old circuit. Then could you run an additional ground from any light on the newer system to the old and ultimately ground the old?

The general rule is that earth wires should run alongside the corresponding live and neutral wires. Also IIRC there is a minimum size for earth wires that are not part of a sheathed cable and not installed in conduit/trunking.

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.

I am just about to completely redo my loft - i.e. put down 270mm insulation and interlocking loftboards, so now would seem to be the ideal time to change out any old wiring while I have access to it.

Seems very sensible

I centainly won't go anywhere near my consumer unit.

I think you are being overly paranoid yes you should be careful but a modern CU competently installed and with the main switch off should not be unduly dangerous.

Is it permissible for me to change out all the wiring (if I can get to the light switches) but for the final connection between the consumer unit and the first junction, and get an electrician to do that last final bit?

Nothing forbidding it, but generally I would reccomend if you want an electrician to be involved at all you should engage with them before starting the work.

 

[winston1]

Any cabling of that age is life expired and should have been replaced long ago.

Not necessarily true. If it is plastic cable its life is expected to be in excess of 100 years. Rubber though is another matter.

 

[mattylad]

FYI I have no earth on most of my light wiring.

I'm not overly worried about it, I use plastic fittings and double insulated lights.
If I sell the house it will need rewiring by the new owner.

Not a problem, I can sleep.

 

[JohnW2]

As you have a bungalow, you could probably run an earth to the ceiling roses fairly easily. Getting to the switches would be harder, unless you have conduit in the walls.

'Running' a earth cable to the ceiling roses (and perhaps even the switches) may well, per se, be fairly easy. However, a 'separate' CPC which does not have 'mechanical protection' is required to have a CSA of at least 4mm² - and getting a 4mm² conductor into the terminal of a ceiling rose (or maybe even a light switch) may be a somewhat different matter (in terms of 'easiness'!)

Kind Regards, John

 

[SUNRAY]

My house was built 1965 and had T&E running CU - lounge light - back bedroom light, from there teed T&E to shaver socket in bathroom. The rest is all twin.
Any more recent alterations are obviousely T&E which includes metal lamp fittings requiring an earth.

 

[JohnW2]

Circuits with no CPC haven't been permitted for almost 60 years. Any cabling of that age is life expired and should have been replaced long ago.

I can't remember the exact dates (and I obviously don't know whether the work was 'permitted' or not at the time it was done) but, even in my very limited experience, I've come across a good few houses (including parts of mine when I acquired it) which have PVC cables without CPCs in lighting circuits. If the OP's cables are PVC, then they will probably last fine for at least another 50 years, even if they are already nearly 60 years old.

Again, you seem to be making assertions on the basis of assumptions which may or may not be correct. For what it's worth, my personal opinion is that you really should first ask the relevant questions and then subsequently make any necessary assertions on the basis of the replies you receive to your questions.

Kind Regards, John

 

[winston1]

However, a 'separate' CPC which does not have 'mechanical protection' is required to have a CSA of at least 4mm² -

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

 

[eveares]

As you have a bungalow, you could probably run an earth to the ceiling roses fairly easily.

Getting to the switches would be harder, unless you have conduit in the walls.

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 ‽