Am I missing something here? 

As part of getting a power connection to my SB I've been asked by UK Power Networks to confirm the loading requirements for my ASHP so they can establish whether I will need a single or triple phase connection.

 

I've had two designs for the heating system, one proposed a 12kw machine, the other an 8kw. Am I correct to think that the kW number is the loading requirement? 

 

Also, does anyone know v the point at which triple phase becomes required, and whether it is significantly more expensive than single? 

 

Cheers 

A 12kW ASHP will probably need no more than 5kW of electricity (12kW is the heat output) and don't forget to tell them it is inverter drive soft start.

 

The DNO starts at a position of zero knowledge about what you are about to build and what supply you need.

 

Depending where you are, 3 phase might be slightly more expensive, or astronomically and prohibitively more expensive (as it would be here)

Thanks @ProDave

 

Is there a place I can see the loading requirements within the technical spec for an ASHP? I looked but couldn't find one for the nibe pumps. 

Can you post a link to the one you are considering and I will see if I can find it.

Thanks @ProDave

 

https://www.nibe.eu/en-gb/products/heat-pumps/air-source-heat-pumps/NIBE-F2040-_-228

9 minutes ago, Tony K said:

Thanks @ProDave

 

https://www.nibe.eu/en-gb/products/heat-pumps/air-source-heat-pumps/NIBE-F2040-_-228

Download the instalation manual from the "documents"  tab; or here https://www.nibe.eu/assets/documents/25739/231846-8.pdf

 

Page 65. Max operating current 23A which at 230V is 5.29kW

 

Starting current is given as 5A

1 hour ago, ProDave said:

Download the instalation manual from the "documents"  tab; or here https://www.nibe.eu/assets/documents/25739/231846-8.pdf

 

Page 65. Max operating current 23A which at 230V is 5.29kW

 

Starting current is given as 5A

 

Brilliant. Thanks @ProDave

 

Is that for the 12 or the 8 kW pump? 

 

8 minutes ago, Tony K said:

 

Brilliant. Thanks @ProDave

 

Is that for the 12 or the 8 kW pump? 

 

12kW

 Cheers @ProDave

1.    I had not heard of Nibe. I take it you approve of them.

 

2. Had another  look at out existing supply and see a spare wire.

So we have a 4 strand cable, with 3 connected and one folded back. Is this possibly an existing 3 phase supply, just not connected?

7 hours ago, saveasteading said:

2. Had another  look at out existing supply and see a spare wire.

So we have a 4 strand cable, with 3 connected and one folded back. Is this possibly an existing 3 phase supply, just not connected?

Post a picture of it please?

 

Photos below. have included the overhead cables in case you can 'read' them.

1. transformer on the left post  and 3 cables to next post, on our land. and single cable off. The transformer post is on the main through run of cables 

2.. the connection, which is live single phase, blue wire bent back.

3. Intermediate post, with cable to the building.

4. all 3 posts from further back

 

4 photos from the connection, to the first post

Looks like 2 phase supply, assuming that it’s actually energised at the cut out.

bit rough leaving the blue conductor not terminated

Edited September 27, 20215 yr by TonyT

6 minutes ago, TonyT said:

Looks like 2 phase supply

 

Does that effectively mean 2 supplies of 240 volts?

Might that be all we need for a domestic supply plus an ASHP?

 

According to the sparky who remade the connection, it was already live, even though unused for many years. 

He didn't mention the blue.

We only asked for a caravan and builder's socket so maybe it is all just ready to use.

I'm pretty sure we are only paying for a single domestic connection. Supplier hasn't been to see.

How many wires are there on the "through" line on the pole where the transformer is (I have tried zooming in but can't see against the backdrop of the trees)

 

Whatever that supply is, I would say the cable size is substandard and the cable in from the pole should be upgraded.

Three. 

We have a plan with all the voltages from a neighbour's old enquiry, so can find a few voltages etc.if that is of any use.

 

Okay so that's a 3 phase supply to the transformer pole.  How about a close up photo of the connections into the transformer?

Edited September 29, 20215 yr by saveasteading

So you have 3 phase to the pole, but that is only a single phase transformer.

 

You could probably get 3 phase to the house, but it would mean upgrading that transformer, it would be interesting to see how much they wanted for that.

Thanks. How do you do that?

 

Is the transformer just to step down from huge voltage to domestic?

 

Unfortunately I may know the answer, as we applied on a different site that fell through.

They wanted £15 k to provide a new transformer, where there was none, and bring in 100m of cable and 2 new poles.

So we think the transformer is about £10k, and then the cable.

We have an enquiry in for an upgrade but it will be  a long time in getting a quote.

 

Do we need 3 phase though? 350m2 of floor area, quite high ceilings but will be well insulated and airtight.

I was thinking we needed 3 phase for domestic + 15kVA ASHP, +water pump, but perhaps that second wire is live and gives us double the power...or could do.

 

Do you mind explaining what 2 phase is for? After many years of sparkies failing to explain,  I think I understand why 3phase is clever and efficient, but 2?

Is it just 2 supplies in one tidy cable?

 

3 phases is as the name suggests 3 separate L cables each one being 120 degrees out of phase with each other.  That is what you would get if they changed the transformer for a 3 phase one, and upgraded the cable from the transformer to your steading.

 

If you want the maximum single phase, ask for an upgrade to 20KVA.  The transformer will probably be okay but the cable between would probably need upgrading.

 

2 phase would be just that, only 2 of the phases connected, a bit pointless (as you can't run 3 phase equipment) but might be handy to give you double the capacity, but you can't get that with that transformer.

 

Your options are:

 

Do nothing but seek clarification of what they rate the capacity in KVA of the existing supply and see if that is enough.

 

Ask for a price for an upgrade to 20KVA single phase

 

Ask for an upgrade to 60KVA 3 phase.

 

Asking for the quotes does not oblige you to proceed if you don't like the answers and can live within the power limit of the existing supply.

 

ok, thanks.

Best we chat it through non-technically with SSEN, as we have a useful contact after 12 non-helpful referrals.

ie all we want is 20kVA by whatever means?