Power Requirements

Michaelwgroves · Mar 14, 2013

Following on from other threads, I need to calculate the load for 11 studios. UK Power networks are due to upgrade the main intake and I have a site meeting next week.
Each studio will have the following load and I need to calculate a base load but I'm not sure what allowances to make for diversity. I'm sure UK Power networks will have a good idea, but I would like to be in a position to hold a sensible conversation.

Shower 10kW
Heating 3kW
Oven/Hob 9kW
Water Heater 3kW
Lights
Sockets

Not sure what is a sensible for lights and sockets but coming home on a cold night, turning the heating on full before jumping in the shower while your girlfriend puts on diner and makes a cup of tea could easily see you hit 100A.
Now that seems mental when I live in a large house with 3 kids and we ony have 60A main fuse and have never tripped it. But that said we have gas heating and share facilities.

What is sensible here, 100A just seems such a safe bet, but I'm sure this will really push up the cost from UK Power networks. Sure I can put in a smaller shower and cheaper oven/hob, but I want a good finish.
I'm sure diversity is the key, but dropping down to 60A seems just too tight.

Any thoughts would be appreciated.

Thanks

Octopus · Mar 14, 2013

Ask your sparky to do some calculations?

keniff · Mar 14, 2013

Diversity will drop it a lot there's figures in the on site guide but on something's there is no diversity like a shower for instance

Engineer54 · Mar 15, 2013

My idea of a Studio is a single combined lounge/bedroom/kitchen room and a separate shower/toilet. Well for a start, you don't need 10 KW showers in these studio's!! lol!! Rule of thumb, add up the breaker ratings and multiply by 0.4 and see what you come up with!! Studio's generally draw very little power, but i doubt very much if 11 of them will sit comfortably on a 60A supply from the DNO!! lol!! ....I'm taking it that you are talking overall?? If your not and talking individually, you'll not see anywhere near 60A being drawn on a single studio unit, if you see half that you'll be doing well and that will only be for a matter of minutes, not hours!! lol!!

Richard Burns · Mar 15, 2013

E54 has it right, The 0.4 rule of thumb is pretty good to use as a likely maximum.
You can have a look in Appendix A in the on site guide that gives a recommendation table A2 that will give you a much higher value than reality but can be used for justification when talking to UKPN.

For the sockets and light consider likely use based on number of points and expected residents. 10A and 3A will probably over cook it.
No diversity for the shower and water heater.
About 20A for the cooker.
don't know what sort of heating is consuming the 3kW so can't say.

Michaelwgroves · Mar 15, 2013

Engineer54 said:
My idea of a Studio is a single combined lounge/bedroom/kitchen room and a separate shower/toilet. Well for a start, you don't need 10 KW showers in these studio's!! lol!! Rule of thumb, add up the breaker ratings and multiply by 0.4 and see what you come up with!! Studio's generally draw very little power, but i doubt very much if 11 of them will sit comfortably on a 60A supply from the DNO!! lol!! ....I'm taking it that you are talking overall?? If your not and talking individually, you'll not see anywhere near 60A being drawn on a single studio unit, if you see half that you'll be doing well and that will only be for a matter of minutes, not hours!! lol!!

Your understanding of a studio is correct, I'm looking at individual loads, I assume UKPN will apply thier own diversity rule for the overall load.

Michaelwgroves · Mar 15, 2013

Richard Burns said:
E54 has it right, The 0.4 rule of thumb is pretty good to use as a likely maximum.
You can have a look in Appendix A in the on site guide that gives a recommendation table A2 that will give you a much higher value than reality but can be used for justification when talking to UKPN.

For the sockets and light consider likely use based on number of points and expected residents. 10A and 3A will probably over cook it.
No diversity for the shower and water heater.
About 20A for the cooker.
don't know what sort of heating is consuming the 3kW so can't say.

0.4 seems sensible,

Heating is Panel Heaters, for clarity I have a mixture of Studio's and 1 bed flats. All will be single occupancy, but 1 bed flats will have extra heater in bedroom.

Where can I find the "Appendix A in the on site guide that gives a recommendation table A2"

Thanks

Richard Burns · Mar 15, 2013

Michaelwgroves said:
Where can I find the "Appendix A in the on site guide that gives a recommendation table A2"

Thanks

The on site guide is a very common book used by electricians

[ElectriciansForums.net] Power Requirements

It references some useful ready reference material for installations.
If you were to look in the book at appendix A you will find table A2.

Panel heaters assume about 11A.

Octopus · Mar 15, 2013

Richard Burns said:
The on site guide is a very common book used by electricians
View attachment 17818
It references some useful ready reference material for installations.
If you were to look in the book at appendix A you will find table A2.

Panel heaters assume about 11A.

But rarely bought by DIYer's or builders

Darkwood · Mar 15, 2013

Ive got this in several colours now .... depends what mood im in to which one i pick ...... saw a brown one on sale in whsmiths other day yrs after the green came out.

Power Requirements

Michaelwgroves

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Octopus

keniff

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Engineer54

Richard Burns

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Michaelwgroves

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Michaelwgroves

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Richard Burns

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Octopus

Darkwood

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