Earthing a porch light

[Zap]

I'm looking to replace an old cracked porch light fitting with a new one. Its wired in as part of the lighting circuit with the switch inside the door. The wire leading out to it is two core. The new fitting that I have bought has only two connectors inside but says that it must be earthed - how do I do this? Any ideas? Many thanks.

 

[holmslaw]

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[Zap]

Thanks for that. I don't mind rewiring but what I don't understand is how I can connect an earth when there isn't a terminal for it on the fitting? Any ideas will be gratefully received.

What has made me wonder on this is that I'm having a new consumer unit fitted soon and as part of signing it off I will have a test of the system. I'm worried that if the light fitting isn't properly earthed it will fail some kind of test.

 

[holmslaw]

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[ricicle]

Are you sure it requires an earth. Is there a seperate terminal bolted on to the framework somewhere ?
If it is class 1 then by the sounds of your wiring it cannot be connected at present.

 

[davelx]

What has made me wonder on this is that I'm having a new consumer unit fitted soon and as part of signing it off I will have a test of the system. I'm worried that if the light fitting isn't properly earthed it will fail some kind of test.

Whoever is fitting the new CU should do a thorough inspection and some test of the existing install BEFOREHAND to identify these sorts of problems and recommend any work that needs doing. He might refuse to install a new CU unless you have those circuits rewired - at the very least he should issue you with and require you to sign a disclaimer to say that he advised you of the dangers and you declined to have the work done.

More worryingly, if he does not do an inspection and tests before changing the CU, there may well be problems with RCD trips that come to light afterwards which will then incur additional expense to rectify, depending on the state of your wiring and the condition of your appliances (assuming that there are circuits that are not currently RCD protected).

 

[Zap]

Thanks to everyone for their advice. I decided to get a new, better, fitting. All is now rewired, earthed and working.

Thanks davelx for the tip on the fitting of the new CU - I will make sure that he tests it all before fitting it! Good advice!

 

[ban-all-sheds]

The wire leading out to it is two core.

Do you mean twin & earth?

 

[Zap]

Sorry, I'm an amateur... just red and black - no earth. But now I've replaced it with twin and earth. Thanks.

 

[ban-all-sheds]

Where did you connect the earth core to? (Not at the light - at the other end)

 

[Zap]

I hope that this will make sense. The original connection was a spur from the main lighting circuit with the switch earthed to a junction box (with the rest of the circuit) and the light leading out from there but with no earth. I have connected the new earth back to this. Should I take out the fuse and leave this to the professionals?

 

[plugwash]

If you find one earth missing you need to assume that others may be missing too.

Do you have a multimeter?

 

[PrinceofDarkness]

Zap: I don't see why you shouldn't carry on with your DIY effort - and I certainly don't see why you should call on a 'professional' as you're soon to have a CU change - and hopefully at least a cursory inspection with it.

It's probably too much to expect you to have any formal test meters - let alone a multimeter. But as a DIY'er you could perform the simple task of checking for earth continuity by using a simple test lamp between live and earth at the new fiiting. You wouldn't have to buy a test lamp, because you could simply whip out the nearest pendant lampholder/flex and use that. If the (proven-working) lamp lights between live and 'earth' then it's likely that you have a reasonable earth connection. If the supply trips out during this operation then it's likely that the circuit is on an RCD - but nonetheless it might also indicate that you have a true earth.


This advice is given on the understanding that you do indeed have an electrician booked for your CU - and that you'll mention your recent DIY work to him........


Lucia.

 

[Zap]

Plugwash and PrinceofDarkness- I do have a multimeter, though I principally use it to test whether things are live or not. I'm not sure that I understand the 'test lamp' procedure.

When my electrician comes in to change the old fuse board for a cu I'll def tell him about the work that has been done by me as I want the end result to be a fully safe system.

 

[PrinceofDarkness]

Let me explain it to you then, Zap: In most systems the earth is more-or-less at the same potential as the neutral. So a simple test lamp connected between live and earth should light up (provided, as I said, that the circuit isn't an RCD circuit, with would result in the RCD tripping).


Perhaps you should leave it to an electrician?



Lucia