under cupboard lighting from lighting circuit

[benjsud]

Hello,

I'm currently fitting a new kitchen and just planning out my wiring. I'm after some clarification on a couple of points:-

1) I would like to wire under cupboard lights to the lighting circuit and have it on a light switch. Most of the ones I've seen in B&Q and Ikea seem to be the sort you plug into a socket and are labelled for 'mains'. Does 'mains' mean 30A socket mains (as I would normally assume) or can it refer to your lighting mains? Therefore can I use this sort of light on my lighting circuit - I was thinking of cutting the plug off and hard wiring into the circuit via a junction box on top of the cupboard - or do I have to buy some other type of light?



2) Assuming I am wiring the cupboard lights to the lighting circuit I shall control it via a 2 gang switch. 1 gang will operate the main ceiling lights and the other gang the under cupboard ones. My question is what is the best way to wire this - via a 3core and earth (1 common live and 2 switch wires as per http://www.flickr.com/photos/8966682@N06/552223479/in/photostream/) or via a twin and earth for each gang?

The main difference I can see between them is with a 3 core the 1 common live wire is effectively powering both ceiling lights and up to 5 cupboard lights whereas with the other option the load is shared over 2 wires. Most under cupboard lights are advertised as 'low voltage' so does this mean they are not placing a large load on the circuit anyway?


Any help would be much appreciated.

Thanks, Ben

 

[ban-all-sheds]

Hello,

I'm currently fitting a new kitchen and just planning out my wiring.

When you apply for Building Regulations approval what do you plan to say will be the way you'll comply with P1?

1) I would like to wire under cupboard lights to the lighting circuit and have it on a light switch. Most of the ones I've seen in B&Q and Ikea seem to be the sort you plug into a socket and are labelled for 'mains'. Does 'mains' mean 30A socket mains (as I would normally assume) or can it refer to your lighting mains? Therefore can I use this sort of light on my lighting circuit - I was thinking of cutting the plug off and hard wiring into the circuit via a junction box on top of the cupboard - or do I have to buy some other type of light?

Are you sure that the "plug" is just a plug, and not a power supply for ELV lighting?

2) Assuming I am wiring the cupboard lights to the lighting circuit I shall control it via a 2 gang switch. 1 gang will operate the main ceiling lights and the other gang the under cupboard ones. My question is what is the best way to wire this - via a 3core and earth (1 common live and 2 switch wires as per http://www.flickr.com/photos/8966682@N06/552223479/in/photostream/) or via a twin and earth for each gang?

If you wire it like that you'll have either the ceiling lights on or the cupboard lights on.

What you won't have is either both on or both off.

I doubt that's what you want.

The main difference I can see between them is with a 3 core the 1 common live wire is effectively powering both ceiling lights and up to 5 cupboard lights whereas with the other option the load is shared over 2 wires.

Whatever cables you use if you have a 2-way switch as shown you'll have one or other of the lights on all of the time, never both on and never both off.

You really need to spend a bit of time learning how light switches work: //www.diynot.com/wiki/electrics:lighting

Most under cupboard lights are advertised as 'low voltage' so does this mean they are not placing a large load on the circuit anyway?

The load on the circuit is the same because your switches go on the LV (230v) side.

You should read this too: //www.diynot.com/wiki/electrics:voltage-bands

 

[benjsud]

Not selected which lights I'm going for yet as am just at planning phase, I will however get the most suitable one.

Think I'm getting confused between 'gang' and 'way'. My understanding is gang=number of switches and way=number of locations you can control light. With this logic I want a 2 gang 1 way switch (a double switch to control 2 different light circuits) - not a 2 way switch.

So what is the best way of wiring this - seems like it is with 2 separate twin and earth going to the double switch?

This way is fine but I was hoping to be able to do it with 3 core as I could just feed one wire to the double switch instead of 2 and avoid chasing the wall.

My reading of the diagram I originally posted is the red wire from the 3 core would supply power to both switches and then the other 2 wires would act as switches to each lighting circuit hence you could control them separately.

 

[ban-all-sheds]

Think I'm getting confused between 'gang' and 'way'. My understanding is gang=number of switches and way=number of locations you can control light. With this logic I want a 2 gang 1 way switch (a double switch to control 2 different light circuits) - not a 2 way switch.

Your diagram shows a 1-gang 2-way switch.

So what is the best way of wiring this - seems like it is with 2 separate twin and earth going to the double switch?

This way is fine but I was hoping to be able to do it with 3 core as I could just feed one wire to the double switch instead of 2 and avoid chasing the wall.

You can use either 2 x twin & earth or 1 x 3-core & earth.

My reading of the diagram I originally posted is the red wire from the 3 core would supply power to both switches and then the other 2 wires would act as switches to each lighting circuit hence you could control them separately.

You should never do electrical work unless you genuinely understand what you're doing and how it works. Following instructions along the lines of "insert his wire into that terminal" without knowing why is a bad idea. True competence is essential.

Your reading of your diagram is very wrong - with the switch in one position Light 1 will be on and Light 2 will be off, in the other position #1 will be off and #2 will be on.

PLEASE spend some time learning what you need to know before you start - don't dive in hoping to muddle through.

• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/electricity.html
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/domesticinstallations.html
  
  
• //www.diynot.com/wiki/electrics:books
  
  
• //www.diynot.com/wiki/electrics
  
  
• //www.diynot.com/wiki/electrics:part-p[/list]
  
  The last link is important - nobody here cares if you break the law or not, but you must make an informed decision on that or in a few years time you may join the increasing number of people coming here asking what to do about the fact that their house sale is stalling because they don't have a Building Regulations completion certificate for some of their electrics.

 

[benjsud]

ok thanks for the help. I think its best to get an electrician around to have a look at it