two circuits in the same switch

[DavidA1982]

Hi all

I want to add under-cabinet lighting to the kitchen. I currently have a normal ceiling light, which is on the downstairs lighting circuit. It is switched from a single switch. I want to power the new under-cabinet lights from the kitchen ring circuit and not the lighting circuit. Is it possible to switch the ceiling light (on the lighting circuit) and the under-cabinet lights (on the kitchen ring circuit) from a single 2-gang switch?

My concern would be that if someone turned off the downstairs lighting circuit to do some work, the switch in the kitchen would still have power as the under-cabinet lights are still carrying electricity. So I assumed that it was not possible.... but then I have a 2-gang switch downstairs that operates the hall light and the landing light, and those lights are on different circuits.

To be absolutely clear: I am not going to do the electrical work myself. I am paying an electrician to do it properly, safely, and in accordance with the law. That electrician could easily answer this question, but he is out of the country for a fortnight and I need to know the answers to allow me to finalise the design and order the kitchen so I would really appreciate your help.
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[EFLImpudence]

Whilst it is not forbidden, as you have described, to have two circuits in one accessory, I would say that the work involved in running cables to do what you want would be no less than (doing it properly and) connecting your under cabinet lights to the lighting circuit.

 

[deadshort]

Hi, if you have a neutral at the existing switch yes. If not you will require to fuse down the supply for the under cabinet lighting to 3a via a fcu, the safest method is to use two switches in separate boxes,or to put the fcu beside the existing light switch.

Regards,

DS

 

[PrenticeBoyofDerry]

As you are taking a spur from the socket circuit, this circuit will require down fusing anyway. So you will need a second single gang to do this, that can be used to switch the under cabinet lights on/off. So no need to have two circuits in same enclosure.

 

[ericmark]

This is a standard method of powering a extractor fan with lights and also have a push button so they can also be powered independent a double pole switch is used for lights so mechanical linked but electrical separate.

 

[deadshort]

This is a standard method of powering a extractor fan with lights and also have a push button so they can also be powered independent a double pole switch is used for lights so mechanical linked but electrical separate.

Yes. When derived from the same circuit! This situation clearly is not.

DS

 

[deadshort]

As you are taking a spur from the socket circuit, this circuit will require down fusing anyway. So you will need a second single gang to do this, that can be used to switch the under cabinet lights on/off. So no need to have two circuits in same enclosure.

Not quite sure you have grasped the situation The op has two supplies


Regards,

DS

 

[stem]

How about connecting a relay to the existing downstairs light circuit and using that to switch the supply to the under-cabinet lights, which would be fed from the ring via a 3A fused connection unit. This way when the downstairs lighting circuit is isolated, the under-cabinet lights are also isolated. If you are still worried, affix a notice like this to the relay.

Untitled

• stem
• 5 Mar 2015
• 1

If you wanted to, you could connect the relay to the existing ceiling light and just use the one switch to operate all of the lights. This also saves having to drop another cable down to the existing switch.

I know that you said you didn't want to connect the under-cabinet lights to the downstairs lighting circuit, but I'm curious as to your reason why?

By the way. It's common in industry and for large buildings such as hotels, pubs, community centres, schools, etc to have banks of grid switches fed from multiple supplies. Often these may include supplies fed from different phases, meaning voltages of 400v can be present between the supplies.

 

[EFLImpudence]

If you wanted to, you could connect the relay to the existing ceiling light and just use the one switch to operate all of the lights. This also saves having to drop another cable down to the existing switch.

If anyone did that then they may as well use the lighting supply for the cabinet lights.

 

[ban-all-sheds]

Are relays allowed as isolation devices?

 

[stem]

If you wanted to, you could connect the relay to the existing ceiling light and just use the one switch to operate all of the lights. This also saves having to drop another cable down to the existing switch.

If anyone did that then they may as well use the lighting supply for the cabinet lights.

You are assuming you know why the OP doesn't want to use the lighting supply, you may be right, but as it's not been stated, that's why I asked the OP the question earlier. It could simply be that the lighting circuit is already overloaded, and so doesn't want to add anything else to it.

 

[DavidA1982]

I know that you said you didn't want to connect the under-cabinet lights to the downstairs lighting circuit, but I'm curious as to your reason why?

Thanks for your help - same goes to everyone else who has commented.

The reason is hard to explain and makes me sound lazy, but basically, I want to minimise the amount of new backboxes and chases I create. This is for reasons of time and disruption rather than expense. It's ambitious, but I don't want to have to pay (and wait) to have the walls skimmed so I'm doing everything I can to avoid chasing out walls. I am quite lucky in that most boxes and chases from the old kitchen are where I need them anyway (the existing kitchen has more sockets than I need, and most electrical appliances are going back in the same position). There is a already a backbox set in to the wall to take the FCU for the under-cabinet lights. It happens to be directly in line (horizontally) with the light switch and only about 50cm away, so it's a simple job to chase out and put a cable in to the switch. That is preferable to cutting a vertical chase up the entire wall, which I think we would need to do if the under-unit lights were powered by the lighting circuit. More importantly, a vertical chase would run right behind the fixing point for the wall unit I want to install. If it is a vertical chase I'd have to change/move the wall units, and I don't want to do that as the way it is planned they will line up exactly with the base units. The way it is planned, it all looks smart. I really don't want to have to install a smaller/bigger wall unit just because there is a chase in the way (there is no service void behind the wall units). I cannot extend the base units by the same amount as I am already at the maximum size for a worktop to be installed in one piece.

I suppose I could just put in a new box a bit further along the wall and cover the existing one over with a blanking plate; or mount the boxes for the FCU etc on the under-side of the wall units, but that would still leave a some chasing out to be done.

The other thing is that I am having downlights put in the kitchen. If you treat each lamp as a separate light, there will be 11 lights in total on the downstairs lighting circuit which seems a lot although there is no science at all behind that concern. I also quite like the idea of being able to turn off the lighting circuit but still have light to work with in the kitchen.

I hope that's clear (?!). To repeat what I said earlier: I will not be installing the electrics myself (although I will be doing the chasing out and installing the metal boxes where I need them). The electrician will be installing all of the cable and appliances and doing everything with the actual electrics.

Thanks again for your help.

 

[stem]

If anyone did that then they may as well use the lighting supply for the cabinet lights.

basically, I want to minimise the amount of new backboxes and chases I create.

OK, you were right with your assumption, you just got lucky this time

 

[ban-all-sheds]

The other thing is that I am having downlights put in the kitchen.

Wouldn't it be better to install lights which are designed to light up rooms, rather than ones which aren't merely not designed to do that but are actually designed to not do it?

 

[DavidA1982]

The other thing is that I am having downlights put in the kitchen.

Wouldn't it be better to install lights which are designed to light up rooms, rather than ones which aren't merely not designed to do that but are actually designed to not do it?

Absolutely. But I am married.

The downlights are going in later, by the way. We are having the room above the kitchen renovated in April and the floorboards are coming up then, so the electrician would rather do it then when he has easier access. Suits me.