Kitchen Lighting, No colours on the wires !!!!

[mondo21]

am trying to replace an old flurescent light with a new fixture in the kitchen.
When I removed the flurescent light I had 4 cables exposed. None identified, and all just the same grey colour. all wires are separate !!
Please see pic attached that I took before removing the Flurescent fixture.
3 wires were connected together while another wire was on its own.
So basically a 2 wire system for the flursecent light.
New light fixture requires L N and E.
I attached 3 wires to N and the single wire to N. The light doesn't come on.
Can someone help me to identify each wire?
There are 2 light switches in the kitchen. one for this light and the other for a outdoor Garden light. Are these connected together ?
At the moment, I removed flurescent light fixture and just have the cables wrapped together as they were when the flurescent light was in place but now even the outdoor light will not come on.
I also attach a pic of the inside of the flurescent light .
Any help please.
Ray

Untitled

• mondo21
• 2 Aug 2013
• 1

Untitled

• mondo21
• 2 Aug 2013
• 1

Untitled

• mondo21
• 2 Aug 2013
• 1

 

[PrenticeBoyofDerry]

The three together look like looped in neutrals, you picture presents them having a grey sheath with black insulation.
So I would hazard a guess if your were to disconnect the separated single that under the grey sheath would be a red core of insulation.

There does look to be a lack of an earth (CPC) though and seems that casing of the fitting has been tied in to neutral.

Best to do a little further investigation with regards to CPC and Identifying live.
You cannot put a metallic fitting on to a lighting circuit with no CPC/earth.
It could be that the CPC is within the sheath of the live core, but this would still need to be continuous back to the board, main earth terminal and supply earth.

 

[mondo21]

Hiya,
I too thought that the 3 wires were nuetral and the single wire is live.
But When I connect 3 wires to new fixture (N) and single wire to new fixture (L). The light doesn't come on.
I tried the new fixture in a seperate room that just had 2 wires and the the light worked fine. The new fixture does require earth.

There are 2 light switches in the kitchen, 1 for the kitchen light.
The other for the garden light.
With the flurescent light remove but cabling still entact, neither light is coming on ?

Is there no way to use the new light without earth ?
would this just mean having to turn of the power when changing a bulb?

Did the old flurescent light need earth but neutral was used?
Was this also a bad idea ?

Thx,

Ray..

 

[sparkwright]

You need an earth. Are you certain there isn't one?

I'm not sure that that is an earth wire connected to the neutral - doesn't definitely look green and yellow. The internal wiring of fluorescents can be many colours.

Usually on a fluorescent the centre terminal can be connected to a prong on the metalwork, and the earth wire from the ceiling gets connected to this.

 

[mondo21]

How do I identify Live Nuetral and earth with a multimeter?

 

[sparkwright]

What three neutrals?

I can only see two, the greyish ones with the blackish insulation.

Is that line that looks to be in the background a wire then?

If so, where does it go?

EDIT; The line I refer to is the pattern on the cupboard door!

 

[mondo21]

Ah I see what you mean.. That line is background.. From the ceiling we have 3 cables connected together into left hand side of the block ... And 1 cable connected to right side... New fixture needs Earth.. How to I ID which is earth.. Is it very dangerous if I don't have earth? Would I have to rewire the house in order to add earth ?

 

[PrenticeBoyofDerry]

Finding the earth/CPC:
*Firstly you require a CPC at the fitting this may not exists, they are normal bare copper when not sleeved or green and yellow or just green depending on the age of wiring.
It seems that a green and yellow wire is visible, but this looks to be attached to the casing of the light (please confirm).
It is possible that the CPC is within the grey sheath of the live (single conductor) or even the grey sheath of the black conductors, the grey sheath may require striping back a little to confirm this.
*If CPC is present then you would require then to test that it is continuous back to the supply.
This can be done in a couple of ways, the normal procedure would be by opening the enclosure of the distribution/fuse board/CU. Isolate prior to removing any covers and prove the system is dead. Then identify the lighting circuit conductors within the board.

**The CPC and the live conductor of the circuit would then be connected together via ideally a terminal block. Known as the "r1(line)+r2(cpc)" test.
Then you can go back to the fitting with a multi-meter and test for continuity using low ohms reading (null out or deduct any surplus values). You will require the circuit when switch closed/on to be offering a low ohms reading, the reading could vary depending on the length of the circuit at that point and the tightness of joints/connections/terminals, plus any damage to either cable.
So would be difficult to guesstimate what you should be getting. 0ohms-6ohms on a closed circuit would normally comply,. But the lower the better.
This in turn would identify your live conductor.
**The second procedure would be by taking a long lead to earth/CPC at circuit end at board, then running lead to location of light fitting in question, then attach multi-meter between long lead and earth/CPC at ceiling. (the meter should be nulled out for added resistance of long lead or that value be deducted from reading taken)
If an earth is not present then one would need to be installed for the use on metallic fittings.
If the earth/CPC is found but cannot be confirmed, it is possible that all CPC will need to be connected up at all fittings and accessories, for continuity to be verified. I would also make sure you do actually have an earth at the supply side or you will not be able to attain a suitable Zs for disconnection times.
Helpful maybe http://www.youtube.com/watch?v=pHIzBSMjy2I