Kitchen Electrics - Lighting and Cooker Upgrades

[merrymeetpete]

Hi Folks,

I am currently doing some work to refurbish a kitchen. I have notified Building Control as the work involves moving a doorway and some electrical work.

Part of the electrical work will be to add cabinet lighting. I am currently thinking of running spurs off the existing lighting main, through the ceiling recessed into the wall and using cable outlets to LV transformers set on top of the cabinets - does anyone have any comments/alternatives? Should the new circuits in the kitchen be protected by RCD as the transformers are in the kitchen?

There is currently a 32amp circuit breaker and supply to a double pole cooker switch which is connected to both the cooker and the hob. The new hob "weighs in" at 6.2kw all told (5 halogen rings) and the new double oven is rated at 4.8kw. Whilst it is somewhat unexpected, I want to allow for the full capacity - thats about 48 amps @ 230v. So the plan is to leave the existing 32 amp supply and dedicate it to the hob and add a second 32 amp cable and circuit breaker to supply the double oven (the oven will consume about 21amps @ 230v). Any comments?

There is plenty of space at the consumer unit for new circuit breakers but I am wonderring at what point the consumer unit is considered to have reached its 100amp capacity? Is it simply a case of adding the values of the various rated circuit breakers together, or is the sum of the fuse capacities allowed to be greater than the consumer unit states it can handle? I am wondering if the increase in the capacity of these appliances will result in needing a consumer unit of higher rating...

There is also a warming drawer and a microwave to be fitted with the oven "stack" that need to be supplied from 13 sockets. Wall space for sockets will be a problem at a lower level - is it acceptable to add sockets to the ring main at the top of the cupboards? Can sockets be added inside cupboards fixed to the cupboard body, or do they need to be fixed to the walls? Is there an acceptable way to add flex to an appliance without upsetting manufacturers (not sure how they react to removal of pre-moulded plugs!).

Any comments or guidance are welcome!

 

[Steve]

Part of the electrical work will be to add cabinet lighting. I am currently thinking of running spurs off the existing lighting main, through the ceiling recessed into the wall and using cable outlets to LV transformers set on top of the cabinets - does anyone have any comments/alternatives? Should the new circuits in the kitchen be protected by RCD as the transformers are in the kitchen?

Any new work involving recessed cables needs to be RCD protected. The easiest way (if you have a 16th edition install) is to use an RCBO at the consumer unit.

There is currently a 32amp circuit breaker and supply to a double pole cooker switch which is connected to both the cooker and the hob. The new hob "weighs in" at 6.2kw all told (5 halogen rings) and the new double oven is rated at 4.8kw. Whilst it is somewhat unexpected, I want to allow for the full capacity - thats about 48 amps @ 230v. So the plan is to leave the existing 32 amp supply and dedicate it to the hob and add a second 32 amp cable and circuit breaker to supply the double oven (the oven will consume about 21amps @ 230v). Any comments?

This sounds ok to me. Remember to provide for an isolator for the oven as well. Dont use cooker ones with sockets. They are fugly. Just a plain single width 45A isolator for each, within 2 metres of the appliance.

By the way, with those ratings, I'd be just as happy to put these appliances both on a single 32A circuit. Its not likely you will be using it all at once, and diversity allows it.

There is plenty of space at the consumer unit for new circuit breakers but I am wonderring at what point the consumer unit is considered to have reached its 100amp capacity? Is it simply a case of adding the values of the various rated circuit breakers together, or is the sum of the fuse capacities allowed to be greater than the consumer unit states it can handle? I am wondering if the increase in the capacity of these appliances will result in needing a consumer unit of higher rating...

Nope. My CU adds up to about 160 amps. Diversity is the rule here. It is the same rule that allows 50 13A double sockets on a 32A ring final. Because they are not all likely to be pulling 13A all at once.

There is also a warming drawer and a microwave to be fitted with the oven "stack" that need to be supplied from 13 sockets. Wall space for sockets will be a problem at a lower level - is it acceptable to add sockets to the ring main at the top of the cupboards? Can sockets be added inside cupboards fixed to the cupboard body, or do they need to be fixed to the walls? Is there an acceptable way to add flex to an appliance without upsetting manufacturers (not sure how they react to removal of pre-moulded plugs!).

On the final point, they dont care. But theres no harm in putting a socket behind the appliance, as long as there is an isolator (20A DP switch) to control that particular socket within reach of the appliance.

 

[mikhailfaradayski]

Hi Folks,

I am currently doing some work to refurbish a kitchen. I have notified Building Control as the work involves moving a doorway and some electrical work.

Part of the electrical work will be to add cabinet lighting. I am currently thinking of running spurs off the existing lighting main, through the ceiling recessed into the wall and using cable outlets to LV transformers set on top of the cabinets - does anyone have any comments/alternatives?

Where do you intend to have the new lights switched from?

Should the new circuits in the kitchen be protected by RCD as the transformers are in the kitchen?

Assuming you are going to just use T+E buried in the walls, i would say yes.

There is currently a 32amp circuit breaker and supply to a double pole cooker switch which is connected to both the cooker and the hob. The new hob "weighs in" at 6.2kw all told (5 halogen rings) and the new double oven is rated at 4.8kw. Whilst it is somewhat unexpected, I want to allow for the full capacity - thats about 48 amps @ 230v. So the plan is to leave the existing 32 amp supply and dedicate it to the hob and add a second 32 amp cable and circuit breaker to supply the double oven (the oven will consume about 21amps @ 230v). Any comments?

nothing wrong with it, but way OTT in my opinion.

There is plenty of space at the consumer unit for new circuit breakers but I am wonderring at what point the consumer unit is considered to have reached its 100amp capacity? Is it simply a case of adding the values of the various rated circuit breakers together, or is the sum of the fuse capacities allowed to be greater than the consumer unit states it can handle? I am wondering if the increase in the capacity of these appliances will result in needing a consumer unit of higher rating...

Assuming you are doing this work yourself, you have saved easily enough cash to fork out for a copy of the regs and the OSG. It would benefit you to have these and consider how diversity can be applied.

There is also a warming drawer and a microwave to be fitted with the oven "stack" that need to be supplied from 13 sockets. Wall space for sockets will be a problem at a lower level - is it acceptable to add sockets to the ring main at the top of the cupboards?

yes, so long as all the parts/connections are accessible for future inspection. Consider the hassle of possibly having to change a fuse in the future aswell.

Can sockets be added inside cupboards fixed to the cupboard body, or do they need to be fixed to the walls?

yes, no - if the sockets can be securely fixed.

Is there an acceptable way to add flex to an appliance without upsetting manufacturers (not sure how they react to removal of pre-moulded plugs!).

Careful design would, in most cases, mean this is not necessary. Why do you think you will need to?

Any comments or guidance are welcome!

 

[merrymeetpete]

Hi Folks - thanks for your swift answers...

Where do you intend to have the new lights switched from?

The light is to be switched from an existing "bank" of switches near the doorway just inside the kitchen... those wont be multiple spurs from the ligting main!!!

Assuming you are doing this work yourself, you have saved easily enough cash to fork out for a copy of the regs and the OSG. It would benefit you to have these and consider how diversity can be applied.

Fair comment... where is it best to get hold of the regs and OSG - btw what is an OSG?

Careful design would, in most cases, mean this is not necessary. Why do you think you will need to?

The warming drawer is very low down in the oven "stack", if I go with a socket at the top of the oven cupboards then a long tail will be needed.

The comment from Steve :

On the final point, they dont care. But theres no harm in putting a socket behind the appliance, as long as there is an isolator (20A DP switch) to control that particular socket within reach of the appliance.

might be a good way forward...

Thanks again for your comments!

 

[ban-all-sheds]

those wont be multiple spurs from the ligting main!!!

The lighting circuit will be a radial - you can have as many branches as you like, and as much as you like on them, within the constraints of the total circuit load.

Fair comment... where is it best to get hold of the regs and OSG - btw what is an OSG?

//www.diynot.com/forums/viewtopic.php?p=75416#75416

 

[mikhailfaradayski]

Fair comment... where is it best to get hold of the regs and OSG - btw what is an OSG?

Amazon sells them. OSG = on site guide. A sort of boiled down version of the regs with pretty pictures. A cracking read

Careful design would, in most cases, mean this is not necessary. Why do you think you will need to?

The warming drawer is very low down in the oven "stack", if I go with a socket at the top of the oven cupboards then a long tail will be needed.

Is there space beneath the warming drawer to put another socket?
BTW, is it one of those expensive drawers thats only just about big enough for 2 medium sized plates and that will never get used once the novelty wears off?

The comment from Steve :

On the final point, they dont care. But theres no harm in putting a socket behind the appliance, as long as there is an isolator (20A DP switch) to control that particular socket within reach of the appliance.

might be a good way forward...

How would you change the fuse if you put the socket behind the appliance?