Connecting Under Cupboards LEDs to Existing Lightswitch

[segandy]

Hi all,

I have just had a new kitchen fitted and am in need of some help with under cupboard lighting.

I’m after having the lights come on at the same time as the regular ceiling lights, ie, using the same switch.
The lights I have are LED strip lights connected to a LED driver with brown & blue 240v terminal at the end (I’ve had it wired to a plug and plugged in and they work great).

My old kitchen had these fitted but when it was pulled out I didn’t get to see how it was wired up.
What I do remember though is that the switch had an extra cable coming out of it with a junction box on the end. I think the blue from the original LED was connected to the blue in the junction box (from the switch).
There is also a socket on top of a cupboard (to power the extractor) which had a blue coming from it connected to the brown form the LED (but inside the junction box)

I’m guessing the blue from the switch provided the ability to turn on and off and the blue from the socket provided the power.

I tried wiring the new one up the same but the LEDs flickered rapidly and gave off a poor light. They also tripped the socket’s MCB at the Consumer Unit.

Other than fitting an in-line switch and plugging it into a socket, is there any other way to power it and connect this up to the main light switch so all lights come on together?

Thanks in advance
Andy

 

[EFLImpudence]

If you really have a neutral (not just a black or blue) wire at the switch you will need a cable from the switch to the driver.
However, this is not the 'usual' way to wire light circuits - via the switch.

If not, then you will need a cable from the light to the driver.

 

[ericmark]

That sounds like a borrowed neutral.

521.8.2 The line and neutral conductors of each final circuit shall be electrically separate from that of every other final circuit, so as to prevent the indirect energizing of a final circuit intended to be isolated.

This means your not allowed to take the line from one circuit and the neutral from another. In the main light switches do not have neutrals so it would seem the installer has taken the line from one circuit and the neutral from another which is very dangerous.

If the "socket on top of a cupboard (to power the extractor)" is fed from the lighting supply it may be allowed but one then comes to.

314.1 Every installation shall be divided into circuits, as necessary, to:
(iii) take account of danger that may arise from the failure of a single circuit such as a lighting circuit.

So the feed should come from the ceiling rose if you want them to work with general lights.

 

[ericmark]

If you really have a neutral (not just a black or blue) wire at the switch you will need a cable from the switch to the driver.
However, this is not the 'usual' way to wire light circuits - via the switch.

If not, then you will need a cable from the light to the driver.

I assume the "I think the blue from the original LED was connected to the blue in the junction box (from the switch). " means line taken from light switch.

And "a socket on top of a cupboard (to power the extractor) which had a blue coming from it connected to the brown form the LED" means neutral from extractor.

And "I tried wiring the new one up the same but the LEDs flickered rapidly and gave off a poor light. They also tripped the socket’s MCB at the Consumer Unit. " means the RCD tripped at consumer unit.

I hope I am wrong!

 

[segandy]

I assume the "I think the blue from the original LED was connected to the blue in the junction box (from the switch). " means line taken from light switch.

And "a socket on top of a cupboard (to power the extractor) which had a blue coming from it connected to the brown form the LED" means neutral from extractor.

And "I tried wiring the new one up the same but the LEDs flickered rapidly and gave off a poor light. They also tripped the socket’s MCB at the Consumer Unit. " means the RCD tripped at consumer unit.

I hope I am wrong!

Yes thats right, its how it was. However, the RCD didnt trip, only the MCB for the sockets (the kitchen had it's own consumer unit fitted for this kitchen installation with 2 MCBs, 1 for the cooker and one for the kitchen sockets, the lights are on a separate fusebox)

From the sounds of your replies, it was originally wired in a pretty dodgy way by using 2 different sources so I dont fancy going down that route.
Any other ideas?

 

[ban-all-sheds]

My idea is that you should get an electrician.

If you can't connect 2 wires without creating a fault that trips a B32 in a few seconds (100's of amps) then:

a) you really should not be doing electrical work

b) you might have damaged something.

 

[ericmark]

I question if really a MCB? Is it in fact a RCBO which is a MCB and RCD combined? If it is a RCBO then likely it has a trip button and some where 0.030A or 30 mA is written on it as well as something like B32.

Running from lights likely needs wiring to ceiling rose.

 

[segandy]

My idea is that you should get an electrician.

Wondered how long it would be before that came up.

I replicated what an electrician installed 13 years ago.

Thanks to the other guys who replied. I get that whatever he did (and what I'm trying to replicate) isnt a good idea, to say the least.

Would an in-line switch and a regular plug on the end be suitable

 

[segandy]

I question if really a MCB? Is it in fact a RCBO which is a MCB and RCD combined? If it is a RCBO then likely it has a trip button and some where 0.030A or 30 mA is written on it as well as something like B32.
.

hi, this is the MCB -

Untitled

• segandy
• 19 May 2015
• 1

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[ericmark]

If you trip that you have done something seriously wrong.

 

[ban-all-sheds]

If you trip that you have done something seriously wrong.

I replicated what an electrician installed 13 years ago.

Sorry - I hadn't realised that when an electrician installed some lighting for you 13 years ago it too flickered briefly and then a fault current of 100's of amps tripped the circuit breaker.

Please get an electrician (but not the same one as before).