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New Wiring For Pendant Lights After Complete House Rewire

Postby rose » Wed Oct 30, 2013 9:19 pm

We have completely re-wired our house. We now want to hang some pendant lights. In some rooms we have down lighters as well as pendant wiring.
We have two lots of grey cables hanging from the ceiling.
One of them has got a clear plastic box shaped thing attached to the wires
and the other cable is just hanging there with the bare wires!

Which one of the cables should we be attaching the pendant lights to?
And then what do we do with the other wire?

Thanks for any replies
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Postby ericmark » Thu Oct 31, 2013 8:28 am

If we look at most ceiling roses there are 8 terminals plus earth clamp in them and one would expect most houses to be wired to take a ceiling rose.

The ceiling rose is both a junction box and a device to hang the pendent from normally rated at 6A with fancy ones like the Maestro Ceiling Master - Polished Brass the bit that connects to lights slides out so you can make the connections on the floor then slide in place once all is done.

I would expect to see three cables and these would be.
1) Live supply
2) Supply to next lamp
3) Switch
For the next lamp to work 1) and 2) would need connecting together and at end of the run there will be no 2) so I would expect to see these in the plastic box with switch wire being the loose one.
So with standard ceiling rose there will be one double and two triple connectors plus earth clamp wired.
Double blue switch wire with brown sleeve on it.
Centre triple brown switch wire, live wire and supply to next lamp.
Other triple blue live wire and supply to next lamp.
And of course all earths with sleeves on them to the earth clamp.

However where down lighters ect have been used often the standard ceiling rose wiring in not used because power supplies and single spot lights don't have the extra centre terminal with is always live. So the switch box is used as a junction box instead. This however means no permanent live at the lamp for emergency lights or fans.

A rewire is normally done in three stages.
First fix the wires and back boxes are installed.
The plaster will then come in.
Second fix the cables are checked and tested in case the plaster has damaged them and sockets, switches and lights fitted.
Third stage a full test and inspection made and readings are recorded on the installation certificate. The installation certificate is then sent to either a scheme operator or the local authority building control who in turn will issue either a compliance certificate if scheme operator or completion certificate if LABC. The completion or compliance certificate in England and Wales are legal requirements under Part P building regulations.

What I don't understand is why a house would be left with dangling wires? One could not issue the installation certificate with wiring in that state and without that the completion or compliance certificate would not be issued.

Clearly people are mortal and provision has to be made to take over jobs where the electrician is unable to complete for what ever reason this would be through LABC and they would normally inspect and decide what they wanted often a electrical installation condition report will be enough.

In theory the Part P rules in England have changed and scheme members are now able to test and issue a compliance certificate in the same way as LABC issues a completion certificate but although the law has changed the scheme providers have not taken this up as far as I am aware so at moment council is only route.

So assuming the electrician who wired the house is unavailable then first port of call will be LABC and see what they want you to do. Some are very helpful others are real pains. This will cost I would guess around £300 so if the electrician who wired is available to finish off the work and issue certificates than that would be best route.

Who ever tests will find out how it is wired and to instruct you how to do a part job seems rather pointless plus it may make getting those certificates harder.

Scotland has similar rules but all the countries and principalities that make up the UK have slightly different rules and I live in Wales so I have not really got involved with the others.

If I was taking over the job I would have to ring out every cable I would not guess. It is just too easy when guessing to make a cable live where the other end is not connected to anything.

Today because of using very low wattage LED or CFL often instead of using dimmer switches the lights are separated into two groups one larger than the other giving three lighting levels so two cables could be both supply to lights from a switch so with for example a 6 lamp pendent you can select 2, 4, or all 6 lamps. Old days we used dimming switches but to use dimmers means very special expensive lamps now that's why methods have changed.

Fittings may also be a problem if the LABC is involved. They want certain number of lights of energy saving type and want the fittings designed so they can't take old tungsten lamps. The little 50mm spot lights come as GZ10, GU10 and L2 with L2 holders having a pin in centre so you can't use GU10 or GZ10 bulbs. Also bayonet bulbs with three side pins instead of two again designed to stop you using tungsten. However even using energy saving bulbs they often will not fit these specials and they are a real pain. First thing a home owner does is swap the bulb holders but have to have silly ones in for LABC inspection. With old house re-wired they should not be required but much down to LABC and how helpful they want to be.
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Postby proptech » Thu Oct 31, 2013 10:16 am

Hi rose
Unless I pop round to you with a test meter, I've no idea. Who did the complete rewire ? and why was it left with bare wires.
Perhaps you could post a photo of these wires, it may then be possible to identify what's what.
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