Kitchen Light Wiring

[Chris147]

Hello,

I'm looking for some help on changing a light in a kitchen. I don't have much electrical experience but have the basics to change simple sockets / switches etc.

This kitchen light wiring (2 switches at either end of the kitchen) isn't something I recognise and hoped someone here could explain in more detail:

From the ceiling I have 3 sets of wires, one of which has an Earth wire the other 2 do not appear to...?

All 3 of the live wires from the ceiling are run into a connector which appears to do nothing.

The remaining 3 Neutral Black wires are run as follows:

The black wire from the set with the earth wire is run into the "L" section of the fitting which has the Live load wire to the light
The other 2 black wires both run into the "N" section of the fitting which also has the Neutral Load wire to the light
The "LOOP" section of the fitting has 3 holders and nothing currently connected
The current fitting is a basic light bulb and wire job, however I want to change this to a chrome 4-spot unit but the wiring doesn't appear to match up!

On the new unit all I have is 4 double connectors: N, Earth, Live all of which match the unit wiring and one double connector which is unmarked.

I would really appreciated some help with this one!

Many thanks

Chris

 

[Doc Hudson]

Welcome to the forum, couple of quick questions. Did you say you have two light switches that both operate the ceiling light? Is there only one ceiling light fitting or do two or more that come on simultaneously? Can you post a post a picture of your wires? Dont assume a black wire is neutral some older wiring use a black as a switched live back to the fitting.

Doc H.

 

[steptoe]

OK Chris,

the one black wire you have on its own is actually a 'switched' live,

it will go to the terminal on your new light marked L

the 2 other blacks go to N

and the earth is self explanatory I think.

the 3 reds can remain in the connector block together, 'doing nothing'- they are in actual fact the live feeds in and out of the light fitting and will be connected to other lights in your house.

remember and turn your power off before you start though,

and it might be a good ideas to arm yourself with some tape to mark up the 'single' black wire so you dont mix it up with the other 2.

 

[ProDave]

The 3 reds in the "connector that appears to do nothing" is the loop, and would normally be in the LOOP section of the fitting.

The single black is the switched live from the switch(es) and should really be sleeved red (or brown) to show it's live

The two blacks are your neutral.

Keep the 3 loop wires in their terminal

The single black (sleeve it in red or brown) goes to the live of your light fitting

The two blacks go to the neutral of your light fitting

ALL earths go to the earth of your light fitting.

Some important things.

BEFORE you do anything TURN OFF the main switch of your consumer unit and make sure the old light no longer works before you touch anything.

Then LABEL all the cables and draw a diagram of EXACTLY what core from what cable goes where, so if it goes wrong you can get it bask as it was.

Check the earthing. If you can't find an earth core in EVERY cable, then your lighting circuit may be very old. In which case DON'T fit a metal light fitting that needs an earth without getting an electrician to check that there really is an earth there suitable for the light. If only 1 cable has an earth, you cannot rely on that earth actually doing anything without testing it.

 

[Chris147]

Thank you both for your quick replies!

Steptoe, when you say the 2 neutral blacks go together does that mean they can be put into the same "N" connector and the other black wire which was going into the old "L" is the switched live which goes into the new Live?

Am I right in thinking the Switched live is the one with the earth wire or is that not always the case?

Thanks

 

[ProDave]

Am I right in thinking the Switched live is the one with the earth wire or is that not always the case?

Thanks

See my reply above re earthing (or lack of it) and don't proceed until you KNOW you have a good earth at the light fitting.

 

[steptoe]

^^

Chris,

it is very important that you check for an earth, all the cables should have an earth present,

well spotted Dave,

if only 1 cable has an earth it is very probably that you do NOT have a good enough earth at your light,

and it would be very advisable NOT to fit a metal fitting in this case.

---------- Post Auto-Merged at 15:58 ---------- Previous post was made at 15:57 ----------

Steptoe, when you say the 2 neutral blacks go together does that mean they can be put into the same "N" connector and the other black wire which was going into the old "L" is the switched live which goes into the new Live?

that is correct.

 

[Doc Hudson]

Check the manufactures instructions, normally a bit of paper in the box. Does it say, "This fitting must be earthed" or words to that effect? Most metal fittings do require an earth, but some are double insulated, (a little symbol with two squares inside each other). If you fitting needs an earth you will need to electrically test the integrity of the existing earth wire, to check it is connected back to the fuse box. Otherwise it could be potentially lethal in the event of a fault. Where about in the country are you Chris?

Doc H.

 

[Chris147]

ProDave: Sorry I must have missed your post as I replied. I will check the earth wires tomorrow since we're almost out of daylight here.

Doc H: I'm in Southwest Scotland

Thanks for all your replies, I think I understand the wiring now but will certainly check the earth wires before I do anything else. The unit is a chrome finish and does require it to be earthed.

Thanks

Chris

 

[ProDave]

Try peeling back the outer sheath from the "un earthed" cables a little and see if there is an earth core lurking that's just been cropped off.

If there isn't, then I fear your lighting circuit has no proper earth, and the one cable that does is probably a later addition. In which case you can't rely on it being connected anywhere.

If you indeed don't have an earth on the lighting, then do you have any other metal light fittings or switches? if so get an electrician to check them and see if they are earthed.

I'm way up in the Highlands so too far for me to come and have a look.

 

[Chris147]

Will try that tomorrow thanks. I've just replaced two double sockets in another room with similar chrome units which required earthing. all the wiring so far has had an earth core there, hopefully I've just missed the earth on those other 2.

Will let you know how things go.

Thanks

Chris

 

[Robin Spark]

Chris, I have given this a little bit of thought and really you need an electrician to come round and verify your earthing. It wont take long to do a simple check of your earthing and polarity at the light fitting and it sounds that the cable with the earth conductor is your wire to the switch which has probably been added at a later date to the loop-in wiring,....unless of course some rodney has cut the earth cores back as Prodave suggests and I have seen this done very recently in a house with modern wiring!

 

[needasparks]

The OP does not mention the switch has been changed but changing the light fitting hints at this.

If a class1 (metalic) light fitting is being fitted with possibly no earthing then there is a chance if a metalic switch is used then a similar problem exists there also.

 

[Chris147]

Hi,

Right on closer inspection the single earth wire is actually 3 earth wires wrapped together...1 for each set of the 3 wires.

I also checked another ceiling light in another room and it also has an earth wire. As far as I'm aware all the electrics in the house have an earth.

Do I still need an electrician to check the wiring or am I safe to proceed with installing the light?

Thanks

Chris

 

[ProDave]

No I would think you would be fine to go and fit your light fitting now.

 

[kme]

IF; and its a big "if", those earth wires are indeed connected properly, then you would be fine.

The only way to verify the integrity of the earth connection is to test it, with the appropriate equipment.

At the end of the day, this is your house. If you go ahead and change the fitting without having the earth checked, it might be alright. Then again............it might not!!!

As others have said, the single black needs to have a bit of red tape wrapped around it, to denote that it is, in fact, a live wire.

I would strongly recommend you have the earthing checked. If it tests satisfactory, you don`t have to lose any sleep over it, do you? The test would also, incidentally, verify a good earth at your "new" chrome sockets. Just because there is an earth wire in the back of the socket doesn`t mean it is correctly connected elsewhere.....

HTH

KME