New Connection Details - Overshare??

[DeeJunFan]

So I'm filling out the form for my new electricity connection, and there are multiple questions about Peak Demand and individual high usage appliances

Should I: a) give as much detail as possible (even though I don't know what I'm doing yet; b) Mushroom them (keep them in the dark and feed them shite)

If I put down the assumed average peak load of 18kw will they limit the supply in some way?

Say for craic's sake if I go and get a 24kw Electric System Boiler?

 

[ProDave]

I went for the B option.  There are now 8 of us sharing a 100KVA transformer and so the default offering they quoted me for was a 12KVA supply.  I just know if I was to quote a lot of high loads, I would have been hit for a charge to upgrade the 100KVA transformer to something bigger.

I actually don't expect to use anything like 12KVA.

I didn't mention a heat pump as they are obsessed with peak start up loads, whereas the heat pump I expect to use will be inverter driven and soft start so won't create a high peak load, but from the experience of others it seemed best not to mention it as they can't compute anything other than heat pump = large switch on surge.

[Guest Alphonsox]

I think I just put down the most likely scenario and sent that in, you're going to get a standard supply unless you tell them you need something special. I can't remember if you are thinking of an ASHP but if you are don't mention it on the form. Sliders got into a huge argument with them over ASHP supply requirements. 

[Declan52]

B is what I done.

[AliG]

I initially told my builder just to apply for a standard one phase (100A) supply.

Then it dawned on me that with all the electrics in the house and the likelihood that I will have an electric car at some point in the future it probably wasn't enough.

It all depends on the electrical devices you will have in the house and the likelihood of them all running at the same time.

One of the big theoretical draws is an induction hob. They can require a 50A fuse although to use this much power they would need to be running 5 rings on boost simultaneously which would seem extremely unlikely.

An oven can need up to 30A

Then you have an ASHP, that might be 10KW so need a 40A supply.

Then what would really push you over the edge is charging an electric car which would need 40A also.

Now it might be that you can manage these things so that you don't run them all together, but it doesn't seem that unlikely a scenario.

The standard 100A supply came along before induction hobs, ASHPs and electric cars would have been considered mainstream items.

I'd be interested in other people's views. Once i realised how likely it was that I might be charging a car up within the next 10 years then a three phase (300A) supply seemed the way to go. I know you can charge them up at night when you aren't using anything else but there are always unexpected situations.

By the looks of things, a new three phase supply might cost around 2000 versus 1000 for a single phase supply. However, Dave correctly points out there is a risk that you get the bill for increasing the size of the local transformer which could add considerably to the cost. A lot depends on your individual use.

 

Edited May 26, 2016 by AliG

[Stones]

51 minutes ago, ProDave said:

I didn't mention a heat pump as they are obsessed with peak start up loads, whereas the heat pump I expect to use will be inverter drive and soft start so won't create a high peak load, but from the experience of others it seemed best not to mention it as they can't compute anything other than heat pump = large switch on surge.

When I filled out my SSE form, there were tick boxes asking if heat pumps were inverter driven / soft start and what the starting current was, so perhaps they are coming round to dealing with the problem.  

Part of our buying our site was the vendor paying to have some overhead lines removed and the site serviced.  As part of that process, I made sure that the new transformer (50KVA) being installed to serve my house and the site next door, was big enough to give each of us the maximum possible single phase supply (23KVA).

[Guest Alphonsox]

24 minutes ago, Stones said:

When I filled out my SSE form, there were tick boxes asking if heat pumps were inverter driven / soft start and what the starting current was, so perhaps they are coming round to dealing with the problem.  

Unfortunately that level of detail and analysis hasn't made it to NIE as yet, for them ASHP = Huge switching current.

[DeeJunFan]

The NIE form i have basically says

What's your peak load?  If you dont enter a figure the assumed max will be 18KVA

Also do I want an earthing terminal???

Sounds like something I would need but can my spark do it cheaper?

[ProDave]

Say YES to an earth terminal. you can always add your own earth (and indeed must for a static caravan) if you want to.

[DeeJunFan]

Brilliant,

Thanks

[AliG]

18kVA is an 80 amp supply. 80 amps x 230V = 18kVA. It is actually a standard 100A supply with an 80A fuse I believe.

If you think that you won't ever use more than 80A at one time then that will be fine.

[ProDave]

I think SSE put the same 100A fuse in every supply. Although  have a "12KVA" supply, it has a 100A fuse like every other house.

[PeterW]

IIRC a 100A fuse will run up to 125A or so before blowing anyway.

The ASHP bit is a myth too - most have a max draw of around COP 1.5 so for a 12Kw it is 8Kw input and 32A supply.That assumes they don't have backup heaters in them !