once again maximun demand sorry!

[wirvine88]

Hi all,
sorry to bring this up again but I cant quite find the answer I need for an assessment

As part of a rewire the ground floor has 20 double 13amp sockets but 9 of these are in the kitchen.

I have been told the kitchen is drawing sockets will have:
13.3 amps from a washer dryer
13.3 amps from a dish washer
1.7 amps from a fridge

How do you work out the maximum demand as I keep getting really high figures!

is it worth going for the kitchen on its own ring of 32 then the other 11 sockets on a 32amp mcb
or does it all go on a 32amp mcb- looking at diversity as i understand it for sockets-13amp for one then 50% for the rest but thqt for just the 13 sockets is = 136amps?

I have spent so much time on this I have completly confused myself so any help would be great!

Cheers
Will

 

[telectrix]

you need to consider diversity. i.e. not every load will be on at the same time. your 2 appliances you mention will each be about 2kw (with heaters on), that's 9A each. to estimate the demand, take it as 9A for 1 appliance then 0.4 x the total of the other loads on the circuit.

 

[dan86]

what the old geezer said ^^

 

[telectrix]

OI?????????

 

[telectrix]

bloody jocks.

 

[ackbarthestar]

Jocks apart, Lets say you clamped the RFC and watched over time the values being displayed.

You would probably find that with everything running you might have a constant 12A and the occasional jump to 20, 25, 30A and then back to a steady 12 - 15A. The regs make an allowance for these types of short overloads so no problems there. .

But how do you justify this by prediction? Good point I here myself say.

This can be achieved by various methods and takes years of experience to know how combinations of different types of load function together.

Probably better in your case to split the circuits so that the 9 circuits in the kitchen are on a separate 32A ring and the rest can either be placed on their own 32A RFC or fused down to a 20A radial.

 

[telectrix]

the 9 circuits in the kitchen.

bloody big kitchen to have 9 circuits. LOL.

 

[micknew]

'Probably better in your case to split the circuits so that the 9 circuits in the kitchen are on a separate 32A ring and the rest can either be placed on their own 32A RFC or fused down to a 20A radial.'

Strong beer in the forum pub tonight (9 circuits)!

 

[ackbarthestar]

'Probably better in your case to split the circuits so that the 9 circuits in the kitchen are on a separate 32A ring and the rest can either be placed on their own 32A RFC or fused down to a 20A radial.'

Strong beer in the forum pub tonight (9 circuits)!

Those bloody socirkets its something to do with the jockets scotets Now I know why they use straps to hold in the jocks.....

 

[ackbarthestar]

the 9 circuits in the kitchen.

bloody big kitchen to have 9 circuits. LOL.

Oh ar, there are some biguns round here.....

 

[Des 56]

Oh ar, there are some biguns round here.....

Electrical trainee exams should now include a question under the diversity label,can they fill ackbarthestars kitchen

 

[Engineer54]

Hi all,
sorry to bring this up again but I cant quite find the answer I need for an assessment

As part of a rewire the ground floor has 20 double 13amp sockets but 9 of these are in the kitchen.

I have been told the kitchen is drawing sockets will have:
13.3 amps from a washer dryer
13.3 amps from a dish washer
1.7 amps from a fridge

How do you work out the maximum demand as I keep getting really high figures!

is it worth going for the kitchen on its own ring of 32 then the other 11 sockets on a 32amp mcb
or does it all go on a 32amp mcb- looking at diversity as i understand it for sockets-13amp for one then 50% for the rest but thqt for just the 13 sockets is = 136amps?

I have spent so much time on this I have completly confused myself so any help would be great!

Cheers
Will

Regardless of anything else, surely commonsense should tell you that a kitchen should be allocated it's own socket circuit. It's the one room in the house/flat where most, if not all the higher rated home appliances are going to be located....

 

[DNS1]

My personal preference is a RFC upstairs, a RFC downstairs and a separate RFC or radial for the kitchen.

I also like to put the kitchen on an RCBO so all the frozen food isn't lost if there's a problem elsewhere in the house.

 

[Engineer54]

My personal preference is a RFC upstairs, a RFC downstairs and a separate RFC or radial for the kitchen.

I also like to put the kitchen on an RCBO so all the frozen food isn't lost if there's a problem elsewhere in the house.

Which was exactly my point!! You need a minimum of 3 socket circuits in an average sized house. The day's of having a single RFC to cover the whole houses power needs, have long since passed. lol!!

 

[telectrix]

we get by quite happily with 2 20A radials. sod all these energy guzzling appliances.

 

[ackbarthestar]

Electrical trainee exams should now include a question under the diversity label,can they fill ackbarthestars kitchen

I'll write the question paper !

 

[ackbarthestar]

I went 'Froggie' on one job once.

Two bedrooms over three floors plus a Kitchen.

One rfc for the kitchen and one 16A radial per floor. I might have got even more excited and used separate radials throughout the kitchen, but I ran out of DB space.

Radials are now the way to go. ............

 

[wirvine88]

Thanks very much for all your help guys,
I love reading these threads when pople get carried away "its surely commen scense..." I am sure it is when your qualified but when your learning theres alot to work out!

Cheers everyone

 

[Knobhead]

Have electrical installation standards lowered to accommodate the lack of skill and knowledge of the installers?
Why in gods name would anyone install a radial unless it is to feed a specific piece of equipment?

Diversity is purely a matter of common sense. I ran my flat as an experiment using a 16A MCB for a week. It never tripped.

 

[Silly Sausage]

I ran my flat as an experiment using a 16A MCB for a week. It never tripped.

When you were away on the Beer Bus that week!