1960's house...

[ldoodle]

My house has 2 core stranded lighting cable. I want to add an additional light fitting and switch so I'm not sure how to proceed. It's grey sheathing with black and red.

Use the same cable (from where?) or use it's more modern equivalent?

This also raises the question of whether I'm limited to certain light fixtures?

Thanks

 

[tew1]

If it was wired in the 60's, is the cable grey PVC or grey rubber? If it's rubber there may be some real problems. The later grey rubber cables tended to hold out a lot better than the black VIR ones though, so they may still be ok. Otherwise, it just isn't earthed, so any light fixtures/switches you install must be plastic or double-insulated (not metal) unless you run a separate earth wire from the fuse box/CU. You can extend with regular 1-1.5mm T&E

 

[ericmark]

Best Practice Guide Guide No.1 Issue 2. Replacing a consumer unit in domestic premises, where lighting circuits have no protective conductor should help.

The question is more about the use of new cable to extend. Clearly if one finds an earth in a cable one would assume it is earthed so although the problem with existing lights has a good answer to add extra is another question.

I hunted for Class II lights for my mothers kitchen and found some 2D units round which worked well. But I am sure I paid double just to get a Class II sticker I am sure same lamp as sold elsewhere.

Earth wires should be laid on the same route as supply cables and would need to be at least 4mm² if not part of the lighting cable so in real terms it's just as easy to replace lighting cables as to add an earth cable.

I have spent hours trying to reconnect earth cables left disconnect pre-1960's and been unable to reconnect all ending up with a worst than before situation.

As to how to correct one has to weigh up all the options from rewire to running extras from the power circuits which always had earths connected. Using switched FCU with a 3A fuse.

 

[tew1]

Earth wires should be laid on the same route as supply cables and would need to be at least 4mm² if not part of the lighting cable

why? what, for lighting circuits? 4mm is only necessary for radial socket circuits surely. For lighting, you only need 1-1.5mm earth, and you could run singles designed for conduit. If an earth-live fault occurred (happened to me), the fuse would blow instantly assuming there is 5amp wire in the fuseholder, and an RCD would trip on any earth fault regardless of the size of the conductors. Weren't earth wires originally run as un-insulated twisted wire clipped alongside the conductors?

 

[Spark123]

Yep, for lighting circuits and any other circuit the minimum size of a separate CPC is 2.5mm Cu if protected against mechanical damage or 4mm Cu if it isn't.
If the CPC is part of a cable, it is in a conduit/duct/trunking or in part of a wiring enclosure then it can be smaller.
In reality you'd replace the cable with an integral CPC.

 

[ericmark]

Having got same problem in my mothers house I did look into what could be done. I came to the conclusion it would need a re-wire. My problem is time just not enough hours in the day. Own house OK little at a time but mothers house once started needs to be finished quickly.

 

[tew1]

thinking about it, how many lights actually need an earth? even most recessed downlights don't need an earth. Most metal lightswitches are tacky and don't look right in old properties anyway (unless they are really nice quality unlacquered brass or similar, but then they only really go with period properties pre-30's)

 

[Spark123]

It isn't easy to say, I'd say a majority modern fancy metal lights need earthed. If you go out of your way you can find class 2 metal fittings.
Worse thing is where there isn't an earth and someone adds twin and earth to it!

 

[riveralt]

thinking about it, how many lights actually need an earth? even most recessed downlights don't need an earth. Most metal lightswitches are tacky and don't look right in old properties anyway (unless they are really nice quality unlacquered brass or similar, but then they only really go with period properties pre-30's)

Do you know what you are talking about.

Reg: 412.2.3.2. - look it up in your Green Book.

it's not ideal, but if you want to fit the grey sheathed cable (T&E) into that light fitting, you'll have to just snip off the Earth (green/yellow) wire as close as possible to the sheathing and leave it unconnected.

 

[tew1]

thinking about it, how many lights actually need an earth? even most recessed downlights don't need an earth. Most metal lightswitches are tacky and don't look right in old properties anyway (unless they are really nice quality unlacquered brass or similar, but then they only really go with period properties pre-30's)

Do you know what you are talking about.

Reg: 412.2.3.2. - look it up in your Green Book.

it's not ideal, but if you want to fit the grey sheathed cable (T&E) into that light fitting, you'll have to just snip off the Earth (green/yellow) wire as close as possible to the sheathing and leave it unconnected.

I mean, most recessed halogen lights have no earth connection because they're double insulated. I was saying that most modern metal fittings look tacky in old properties anyway unless it's a bathroom or kitchen, so anyone with any design sense wouldn't be having an earth problem

 

[riveralt]

I mean, most recessed halogen lights have no earth connection because they're double insulated. I was saying that most modern metal fittings look tacky in old properties anyway unless it's a bathroom or kitchen, so anyone with any design sense wouldn't be having an earth problem

So when you fitted your downlights in between your RSJ's how did you test the Earth loop impedance?

Here's a random installation manual of a class 2 luminaire I pulled of TLC's website

http://www.tlc-direct.co.uk/Technical/DataSheets/JCC/GUFRD50.pdf

Notice anything.

 

[flameport]

thinking about it, how many lights actually need an earth?

A substantial number of them.
An earth is required at all points anyway, regardless of what is fitted there.

even most recessed downlights don't need an earth.

Some may not. Plenty of them do, and they usually have connections like this:

Untitled

• flameport
• 28 Jul 2013
• 1

Most metal lightswitches are tacky and don't look right in old properties anyway (unless they are really nice quality unlacquered brass or similar, but then they only really go with period properties pre-30's)

You may not like them, but plenty of people do want metal light switches.
Even with plastic switches, there is still the problem of the metal fixing screws.

 

[tew1]

thinking about it, how many lights actually need an earth?

A substantial number of them.
An earth is required at all points anyway, regardless of what is fitted there.

even most recessed downlights don't need an earth.

Some may not. Plenty of them do, and they usually have connections like this:

Untitled

• flameport
• 28 Jul 2013
• 1

Maybe I'm just venting, but that earth connection isn't doing anything. It's just terminating on a random piece of metal that isn't actually connected to anything that could come into contact with the conductors, or anything you will touch.

 

[riveralt]

Maybe I'm just venting, but that earth connection isn't doing anything. It's just terminating on a random piece of metal that isn't actually connected to anything that could come into contact with the conductors, or anything you will touch.

You're just winding us up now - having a bit of a laugh - kept quiet for year and because of the warm weather decided to come out and play.

 

[tew1]

Maybe I'm just venting, but that earth connection isn't doing anything. It's just terminating on a random piece of metal that isn't actually connected to anything that could come into contact with the conductors, or anything you will touch.

You're just winding us up now - having a bit of a laugh - kept quiet for year and because of the warm weather decided to come out and play.

I forgot I had an account, logged on to ask a question and got a bit hooked. whoops. come on, that earth has no purpose. Now these are nice (expensive) metal switches http://www.forbesandlomax.com/the-unlacquered-brass-range.html but they wouldn't look good in a 1960's house