Hi,

 

I've been reading quitely for a while now (this forum has incredible knowledge, thank you), waiting to get the keys to my next project. It's a bungalow conversion, raising the roof for bedrooms upstairs.

 

I want to remove the overhead single phase supply, as it'll get in the way of the new roof work, and planned external wall insulation.

 

I'd also like for it to enter the building in the plant room, out of the way, convenient.

 

It would be nice, if i could get the neighbours overhead supply moved too, if it's not to much more, although not essential.

 

I've been given the following options;

 

1. single phase to a wall mounted (will complicate and compromise the EWI installation) box outside the plant room - £2649

2. 2 x single phase connections, to include the neighbours - £3073

3. three phase to a wall mounted box as per 1- £3083

 

I asked if it was possible to have the supply enter the building underground, this is no longer possible due to policy. So we got talking about kiosks;

 

4. single phase to a kiosk next to the electricity pole (next to the rubbish bins) - £2100ish

5. 2 x single phase connections to include neighbours, mine in a kiosk, neighbours wall mounted - £2927

6. three phase to a kiosk as per 4. £2527

7. three phase for me + single phase for neighbour, not worth it, it would be two seperate jobs.

 

What would you chose?

 

 

 

 

Edited June 28, 20233 yr by LiamJones
typo

I should add what i intend to do with the power, and why i'm considering three phase.

 

8kw solar on the roof, 3 phase gives me g98 approval, single phase would be a g99 application (which i havent done, so it's still possible)

5kw ASHP

 

future proofing is a nice to have, although from reading on here, maybe the need for 3p is a bit of a myth.

1 hour ago, LiamJones said:

5kw ASHP

Sorry for the digression, but how did you arrive at this size? Is it a new, insulated and airtight dwelling?

The quotes seem very favourable, do they include the whole job or have you asked them to remove the contestable works already?

54 minutes ago, Nickfromwales said:

Sorry for the digression, but how did you arrive at this size? Is it a new, insulated and airtight dwelling?

The quotes seem very favourable, do they include the whole job or have you asked them to remove the contestable works already?

hey, I ran a spreadsheet on this forum and have a copy of phpp. Both came out around 3kw peak heating demand. Will be focussing on air tightness, increasing insulation throughout and reducing thermal bridging where possible. 
 

quotes include me doing the digging

quote seem reasonable. I'd suggest getting the supply to a kiosk at the site edge for you and attached to neighbour's wall to get rid of both those overhead cables. you can then run from the kiosk underground in to the house as you've suggested you'd prefer.

 

as to the 3-phase/single phase question I'd suggest that's a matter of preference. if it wasn't for the neighbours overhead cable I'd say 3phase is a no-brainer but I would really want that neighbour's overhead out of the way and so it looks like single phase for both properties and chance your luck with a G99 application. so option 5. for £800 to get rid of that cable? I wouldn't even hesitate!

3 hours ago, Thorfun said:

If it wasn't for the neighbours overhead cable I'd say 3phase is a no-brainer but I would really want that neighbour's overhead out of the way and so it looks like single phase for both properties and chance your luck with a G99 application.

Yeah, I think that's where i'm at with it. If i can get g99 for 8kw solar, then i dont think i need the 3 phase. The neighbours overhead cable is the bigger priority.

 

I could always run 5 core SWA from the kiosk to the house, to allow for 3 phase upgrade in the future, if required.

1 hour ago, LiamJones said:

I could always run 5 core SWA from the kiosk to the house, to allow for 3 phase upgrade in the future, if required.

You might change your mind when you see the price of it!!

10 minutes ago, Thorfun said:

You might change your mind when you see the price of it!!

Plus the costs of a retro-upgrade to 3ph end-of-line equipment.

It would make zero sense to retro-fit, so decide now, or forever hold my peace.

Ended up going with 3 phase to just mine. They ended up wanting a load more for the neighbours.

 

Heres the kiosk, roof slab is cast just waiting a few more days to cure then will attempt to lift it into position on a bed of mortar.

 

 

I also ended up getting g99 approval for 8kw on a single phase, so I’ve got all the options available. Nice chunky 25mm 5 core to the house and 2 x 10mm 5 core for 2 x 22kw car chargers.