Two Core Lighting Cable

[Wesley]

In the process of renewing a light fitting in our kitchen today, I discovered that our lighting cables have only two wires - live and neutral - no earth! This is probably the original wiring from the mid 1960's.

The cables are individually coated in plastic within a grey plastic sleeve but are multistrand and not the single strand copper wire of today.

I had a hell of a job trying to fit these multistrand wires into the fitting and gave up in the end. I solved the problem by using a plastic terminal block and running modern cable from this to the light fitting but the earth terminal in the fitting is not connected to anything.

It works but I am wondering how this fits in with modern wiring regulations especially since part P has come into force. Would there be any problems if we decided to sell the house or rent it out?

[John Rumm]

Yup, common for the time.

The fact that the earth terminal exists on the light fitting suggests that it might be a class I device (i.e. must be earthed), If this is the case then it is not suitable for your circuit.

Part P has no bearing, since changing any fitting "like for like" in any location is non notifiable.

However fitting a metal clad accessory (e.g. a switch) or lamp fitting is considered poor practice. Really the circuit ought to be rewired. However chapter and verse can be found here:

[SteveW]

There's nothing wrong with it, but you should not use any metal fitting that needs earthing!

If you really want metal fittings, then you need double insulated ones (I don't know if they are available or not); or to replace the wiring; or to add a separate earth wire.

SteveW

[Lobster]

It doesn't meet modern regs, obviously, though there's no compulsion to upgrade every time the regs change. If you rent out, you're legally responsible for the electrical safety of your tenants; the only way to cover yourself against liability is to get the property tested, and any report would flag this and recommend rewiring; either way, without or without a test you'd be totally screwed if a tenant electrocuted themselves as a result.

In terms of selling - if a buyer had any electrical report done, this would get flagged, and expect them to try and use it as a negotiating chip.

Also, I'd have thought, very poor practice to have solved it as the OP has done: from the sound of it the new fitting will have new twin-and-earth cable entering it (with the CPC going nowhere) - which means that anybody replacing it in future will likely assume that the circuit is earthed. (And if that was your tenant, electrocuted as a result, expect a judge to nail you to the wall!)

David

[meow2222]

Use either a double insulated metal light fitting (marked [[]] ) or a plast= ic one, then its as safe as on a modern circuit, though still not regs comp= liant, and presumably with no RCD. For selling its likely it wouldn't be pi= cked up. For letting it should be sorted out.

NT

[Dave Plowman (News)]

It will still be perfectly safe provided you stick to wiring accessories and fittings that are suitable. Ie, don't require an earth. In practice, no metal plate switches or light fittings which need an earth - look for ones with the double insulated symbol if changing from an ordinary pendant type. If you are really paranoid, use nylon screws to fix the switches to the backing boxes.

[John Rumm]

While there is no compulsion to upgrade existing stuff to current regs, any new work you do should be to current standards. Hence these circuits are a pain since even something as trivial as moving a light fitting or adding an extra switch ought to trigger a complete rewire of the circuit.

Now sure what else he could do in the circumstances... sleeving the CPC and terminating it in a insulated crimp for example, but not connecting to the fitting might be an indication that it is decorative. However you really need one of these:

[meow2222]

compliant.

NT

[Harry Bloomfield]

Wesley formulated on Thursday :

3 strands will be 3/.029. 7 strands (unlikely) will be 7/.029

[Dave Plowman (News)]

Would be some lighting circuit that used 7/029. ;-)

[Harry Bloomfield]

Dave Plowman (News) explained :

I agree, which was why I said 'unlikely'.

There was a rarely used smaller size than 3/.029 I think, what was it?

[Dave Plowman (News)]

[sm_jamieson]

My house was like that, but in addition some kind of braided earth wires were run around the place and fixed to the joists with drawing pins occasionally. The stuff ran through the original plaster in places, so it must have been original.

Simon.

[Harry Bloomfield]

That rings a bell!

[Dave Plowman (News)]

No - that's usually 0.75mm²...

[Harry Bloomfield]

lol

[Wesley]

In light of the above, I'm now considering getting some quotes to have the old 1960's fusebox replaced with a modern consumer unit and having all the circuits tested in the process. What would be a 'ballpark figure' for this and are there any likely problems?

Don't knock me down in the rush :-)

[John Rumm]

That was common used for socket earthing (where a larger CSA twin cable would take the L&N in a radial to the sockets) - the earth seemed to often follow a completely different route.

[John Rumm]

You may find that the sparks is reluctant to replace the fusebox without also rewiring the lighting circuits, since connecting them to the new CU would not be compliant with the regs in force now.

£350 and up - depends on the number of circuits, size of the property and the general state of the wiring.

Yup, plenty - in particular item 4 on this list:

can find there are a bunch of faults in the wiring that don't show up at the moment, but would come to light when the new CU goes in.

[meow2222]

First inspection certs need to be interpreted, trivial matters are sometime= s flagged as serious, things that dont need doing are sometimes flagged as = needing doing.

2nd reconnecting circuits to the new CU is liable to cause instant RCD trip= ping, leaving you needing significantly more work, inclduing partial rewiri= ng.

Tread with wariness. Or do your own inspection, its free.

NT