kitchen submain

[gavin.sibley]

Hello all,

I have a customer who wants to run a submain to a new kitchen. He will then be having 1 x 32 amp ring main, 2 x 32 amp cooker circuits and would also like eventually to add a feed to the garage. Even with diversity I have calculated the total load to be around 65 amps, meaning a 16mm submain. Does this sound right and/or feasible? Or does anyone else have any better suggestions?

I am starting to wonder whether to run the garage on a seperate supply right back to main board to drop load for new kitchen DB.

Any suggestions or thoughts?

Many thanks,
Gavin

 

[Spoon]

I have a few questions.
What size cooker is going in?
Are the 2 x 32A circuits for 2 cookers & hobs?
Cant you add the new kitchen circuits to the existing CU?
What is going to be used in the garage?
I think your calcs for the load might be a bit high...

 

[Octopus]

As the designer its YOUR responsibility to confirm or not whether a solution is within the regs. Letting a client decide is not a good idea.

 

[gavin.sibley]

I have never once suggested the client was deciding anything, I'm merely asking a question to back something up I calculated as it seemed high and I'm wondering whether it was just my Monday morning maths letting me down.

The two 32a circuits are for a hob and integrated oven.

I can add to existing CU however I thought a submain with seperate DB would be a good solution if possible to save massive cable runs.

Garage is just a light and a few sockets for drill chargers etc.

Hope that helps.

Cheers,
Gav

 

[Spoon]

You know best with regards to new sub-board or circuits back to main CU as you have seen the place.
How long is the run fron the CU to the kitchen?
You need to ask the customer what oven he is getting, so you can work out the power better.

 

[DPG]

I have never once suggested the client was deciding anything, I'm merely asking a question to back something up I calculated as it seemed high and I'm wondering whether it was just my Monday morning maths letting me down.

The two 32a circuits are for a hob and integrated oven.

I can add to existing CU however I thought a submain with seperate DB would be a good solution if possible to save massive cable runs.

Garage is just a light and a few sockets for drill chargers etc.

Hope that helps.

Cheers,
Gav

To be fair you did say the customer wants to run it as a submain. Daz

 

[Selfmade]

I agree with Spoon above. If it's a typical modern domestic oven it will probably use about 10A. The hob (again typical domestic) will use around 26A. With diversity as per OSG, that's about 19A, so you could have one 20A circuit instead of the 2 x 32s you are planning! Even if you do decide on 2 x 32s, you could still count it as 1 x 20A for the purpose of maximum demand for the submain. I am assuming this is a purely domestic kitchen - I don't know about commercial. Anyway, don't assume my figures are right - get the ratings for appliances that will be fitted.

 

[Octopus]

The biggest issue you face is the cable run to the "new" board and how you provide RCD protection

 

[Guest55]

50A mcb >>>> 10mm t&e>>>>>> 4 way mini CU>>>> 3 final circuits and 1 spare.

all day long ;-).

though at which point you insert your rcd protection will require clear thinking.

 

[Guest55]

if it was me , i'd try not to rcd the submains and have rcbo's in the remote CU for each of the kitchen , cooker & garage.
will save on walking when resetting a trip.
;-)

 

[Engineer54]

Another remote CU where it is probably not needed, not unless the place is a bloody mansion!!

Oh and you don't need 2 X 32A circuits to provide power for a hob and oven, that together come in at 15KW or under!!

 

[GLENNSPARK]

if it was me , i'd try not to rcd the submains and have rcbo's in the remote CU for each of the kitchen , cooker & garage.
will save on walking when resetting a trip.
;-)

well as it`l be his bird/missus that will be allocated the kitchen i dont see that this is is an issue...really..is it..