HELP!!! Ceiling light fault is driving me mad!

[pedro163]

Can anyone help?

We've changed over our ceiling light. With wires correctly connected [Black to Blue. Brown to Red] and fuse switch back to on, the light comes on, but the wall switch doesn't work? Where I am going wrong - sure it's probably obvious to everyone but me, but it's driving me insane! Any ideas...

Yours frustrated!

 

[JohnD]

I bet you've missed out, or wrongly connected, the cable to the switch. In many cases the "live" travels from the ceiling to the switch in red, and comes back in black. People were supposed to put red sleeving round the black from the switch to show it was "live" when switched on, but often didn't. Have another look in the "for reference" section at light circuits, especially the ceiling to switch part.

If you can lay your hands on a digital camera and post a pic of the connections and cables at the ceiling, it may help. I asssume from what you say that you have no fuses blowing/MCBs tripping, and the lights in all other rooms are working, which is a good start.

 

[pedro163]

Your right - no fuses have blown/tripped fuse box, and the lights in all other rooms are working fine.

I've not changed anything at the wall switches. The wires coming from the ceiling are:

Red [two]
Black [two]
Earth [no earth on new ceiling light]
Red [single] - not used with old ceiling light

From light fixture there is:
Blue
Brown

Black [two separate twisted together] into blue and Red [again, two twisted] into Brown. I thought initially that this may have been where the problem was, but have double-checked, and nothing. I've even swapped blue into red and brown into black, and it's the same. Wall switch does nothing to turn lights off????

 

[JohnD]

I wasn't suggesting you'd changed anything at the wall switch.

Have a look at the "for reference" section (see the top of this page).

I think that one pair of the wires you've got in the incoming supply, and the other pair probably goes to the switch. Do you have a grey or white sheath visible around each set of "one red/one black/one earth" ?


Read the "for reference" on lighting circuits before you reply. It will help you.

 

[pedro163]

Ref. grey sheath around wires, yes I do. Thanks for the 'for reference' advice - I'll check it out.

 

[pedro163]

Right, this is making no sense at all. Sorry, call me thick [mainly tired] but I can't suss this.

Any help much appreciated.

Flex from the ceiling includes 2x red [both twisted together], 2x black [both twisted together], 1x earth, 1x red

When I took the old light down, the earth was connected [no earth needed on this one], the blue from light went into black, and the brown from light went into red.

The new light has blue and brown to be connected. The light is on from fusebox, but can't be switched on or off at wall. The light can be switched on at the wall in the kitchen or in the lounge [two way].

Sorry, if it's pleading obvious but electrics is not my thing - so I'll need explanation that a 2 year old could explain.

 

[pedro163]

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[BJS_Spark]

Edit!

Ignore that suggestion, get a multimeter and check what the connections are with the circuit dead.

 

[Qedelec]

Pity its not a clearer picture, I would love to know how there are 3 reds and two blacks from two cables

 

[pedro163]

OK. There's actually three cables:

1) Red, Black and Earth
2) Red, Black and Earth
3) Red and Earth only

Make any sense to anyone?

 

[JohnD]

Have a look behind the switchplate and see what cables you find in there.

The "red only" - does it have a small sheath, or could there have been a black that has been cut off?

 

[pedro163]

It's just the earth and red on its own - definitely never a black there.

Behind the switch plate on the wall is three red wires - L1 and L2 [top] and one other at bottom.

Can't understand why it was working fine with old light and now nothing?!

 

[JohnD]

Aha! You have a two-way switch!

Of the three red wires going into the switch, do two come out of a single grey sheath, and is the other the "red no black" that you mentioned earlier? Which of them goes into "COM" and where does the single red go?

What have you got in the other two-way switch at the other end of the room?

 

[pedro163]

Yeah, there's one light switch in kitchen and one in the lounge to turn lounge light on.

The switch plate at the wall - there's two grey flex - 1 with two red wires coming out of [going to L1 and L2], and 1 with 1 red wire coming out of going to bottom.

The wires coming out of the ceiling - two come out of a single grey sheath/flex, and the other is the "red no black" that you mentioned earlier?

Sorry, not sure what "COM" is? The single red is [capped?] off as you can see in the pic below. The other two red I assumed are twisted together in put into the brown on the light, with the black going into blue??

[/img]

 

[Qedelec]

Right are you sitting comfortably.
Cap off the two reds in the ceiling with a insulated terminal block, the one on that red will do. connet the terminal block on the new fitting thus. Black to Blue and 'single' red to Brown.