Electrical supply upgrade

Hi

I am in the process of having a granny annexe built in my back garden.  I am requesting an upgrade to my electrical supply with http://www.northernpowergrid.com/

I live in a 2 bedroom bungalow with a ring main for lights and one for sockets.  I have an electric oven and hob nd the other big item is a large Mira shower.  The annexe will be 1 bedroom with a ring main for lights and same for sockets, same arrangement for cooker and shower.

Could someone please advise on where to start with working this out .

Thanks

remetiffy said:

Hi

I am in the process of having a granny annexe built in my back garden.  I am requesting an upgrade to my electrical supply with http://www.northernpowergrid.com/

I live in a 2 bedroom bungalow with a ring main for lights and one for sockets.  I have an electric oven and hob nd the other big item is a large Mira shower.  The annexe will be 1 bedroom with a ring main for lights and same for sockets, same arrangement for cooker and shower.

Could someone please advise on where to start with working this out .

Thanks

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Is the annex going to be connected to the same supply (i.e treated as one dwelling with one electricity meter) or do you want it to have it's own supply, meter and individual bill?

Hi  Sorry I should have made that clear.  It will be fed from the main dwelling.

Got nothing to do with northern power then, just get an electrician..

john..

Yes as already answered, it's a job for an electrician. The option you were looking at would only apply if you wanted the annex to be treated as s separate building with it's own supply.

Hi

I have to apply to Northern Power for the supply to be upgraded and the online form is asking me the questions I posted above.  

remetiffy said:

Hi

I have to apply to Northern Power for the supply to be upgraded and the online form is asking me the questions I posted above.  

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Welcome to the forum.

Why do you want a supply upgrade?

You already have a normal domestic supply at the property yes?

What makes you think that you need the supply upgraded?

There are 7 people living in my house, all electric cooking, 9.5kW shower, being used 7 times per day without the showering of the manky mutts.

4 bedrooms, loads of IT kit, external sheds with power supplies, external lighting, and all running off a conventional single phase domestic supply.

remetiffy said:

I have to apply to Northern Power for the supply to be upgraded

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Said who?

We run two 8.5KW showers from a standard 100A incomer.

Hi

Thanks for all the replies.  I've had an electrician look at it and he said the main dwelling only has a 60A fuse.  He thought there could potentially be a problem if for example both showers were used at the same time as both ovens and hobs. plus a few of the outlets with high demand appliances plugged in.  

not wanting to state the obvious, but why dont you ask the sparky who wants a larger supply to give you the info you need?

Because the sparky took a look, said what he said then left.  I am now trying to work this out.  If I am given the answer to the question in the original post then I will do the sums and that will allow me to find out if I do or do not require the supply upgrading.  

There is a thing called diversity. It is very unlikley both showers will be in use AND both ovens on.

It may well be you have a very old under rated supply.  I was asked to fit a shower to a house once, and I was confronted with a pair of what looked like 10mm meter tails emerging from the wall into the CU. not even it's own cut out. It was clearly a shared supply from the adjoining house next door, so I declined and told them to get a quote to upgrade the supply. I never heard back, so either the quote for the upgrade was too high, or they found another electrician willing to just install the shower regardless (eek)

It would be useful to know what the electrician actually said, or see a photo of your supply head, meter and consumer unit.

Alternatively re think the showers. Fit an unvented hot water tank (mains pressure) and a thermostatic mixer shower and you will have the best shower you have ever had, and would not want to go back to an electric shower ever again (bloody hell an electrician talking himself out of work)

Hi

Please find below a photo om my supply into the house.  The sparky who took a look did mention something about there being a "3 phase knockout" installed. 

looks like TP, but it also looks like the other 2 phases feed an adjacent property

The issue there is substandard meter tails in and out of the meter. From the henley blocks onwards the tails look reasonable.(though you really want a new consumer unit as part of the extension and a LOT of tidying up)

In that situation I would (and have) report that as a "fault" as "dangerous" meter tails. Use the "dangerous" word and that usually gets someone out the same day and it will take them about 15 minutes to replace those tails and as it's a repair, it's free of charge. Then when the guy is there find out for sure what size fuse in in the carrier and see if it can be uprated to 80 or 100A

If that is TP it may not be so bad, but if that is a single phase incomer, then feeding out to two other properties I doubt you will just get a bigger fuse fitted that's when it will start to cost you and then to be honest getting a new supply into the annex is starting to look a very much easier option.

OK  I think I need speak to the next door neighbour.

In the mean time if I can go back to the original question is there a way to work out the demand?  Maybe a formula where you add up all the appliances and find an average or something.

thanks again for all the help so far.

Well as a ballpark, say two 9KW showers = 18KW and a bit got other general usage at the time, and ask for a 21KVA supply. That's pretty normal for a domestic supply.

See what they come back with for an upgrade, then ask the cost for the same new supply to the annex.

remetiffy said:

In the mean time if I can go back to the original question is there a way to work out the demand?  Maybe a formula where you add up all the appliances and find an average or something.

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ProDave said:

There is a thing called diversity.

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But as @ProDave said, I'd try and avoid the electric showers route altogether anyway.

Before you apply for a supply upgrade I would get Northern Power out to look at the existing arrangement/ask for a cutout upgrade.

Also might want to shop around for electricians as this one seems to have mid-advised you to chuck money away for no reason.

Back to the OP .... How do you heat your house and how do you plan to heat the annex?