New Single Phase Electric Supply

[PaulD]

Hi, first post here ... I've got a large four bedroom class Q in rural Derbyshire. Nearest connection point to the High Voltage network is around 600 metres away. I own all the land inbetween. Western Power have sent a quote through, and well, it was a little higher than expected ! (in excess of £40K) ... They want to go overhead with poles with a pole mounted transformer. I'd actually be happier to go underground, and would have done all the trench work, and put cable/ducting in myself to save costs, but Western Power said this would increase costs considerably due to them installing a ground mounted transformer. The majority of the cost was "contestable" so I can get a third party to do this work ... does anybody have any first hand experience of anybody who can quote for this work ? ... I guess the other option is going "off grid" with solar/battery and a backup generator, decisions decisions ... any ideas anyone ?

[Marvin]

I my humble opinion, if this is the only 2 choices, this is the first time I have seen the decision about on or off grid be clearly off the grid, along with the quote.

[Roundtuit]

That's ridiculous.  You can maybe put a boundary kiosk in, and let them run overhead to the kiosk if they must, then bury the supply to the house.

[Johnnyt]

Couldn’t they mount an upgraded transformer on the existing pole 600m away and then lay the subterranean 3 phase cable to your new property.

This is what we did on a 175m run cost £3,400 we dug trench and SPEN laid 185mm 3 phase and provided temp site supply.

The existing pole mounted transformer was adequate for feeding 3 new supplies.

[Bonner]

Do you have a breakdown of the costs showing which parts are contestable? Depending on the works, you may need a DNO approved contractor or you can DIY to their spec. As mentioned, best solution would be a pole mounted transformer connected to a meter kiosk near your boundary. Then you can run your own cable underground to the house.

[joth]

4 hours ago, Bonner said:

Do you have a breakdown of the costs showing which parts are contestable? Depending on the works, you may need a DNO approved contractor or you can DIY to their spec. As mentioned, best solution would be a pole mounted transformer connected to a meter kiosk near your boundary. Then you can run your own cable underground to the house.

 

+1 to this.

 

Side comment that 600m of 240V from kiosk to house will be less efficient than the high voltage distribution to a transformer nearer the property, and you'll end up paying for most of those power losses (behind the meter) rather than WPN.  Oversizing the 3ph cable from kiosk to house will minimize this, as will distributing loads across the phases. Also any solar PV that reduces import will improve the overall efficiency - so long as it's on the same phase(s) that the consumption is on.

 

 

[ProDave]

600M of underground 240V cable of sufficient size not to have excessive volt drop, is going to be expensive and you are not just going to buy it from a wholesaler, That is direct from the manufacturer stuff, think what comes on a dirty great big cable drum on a trailer towed behind the DNO's vehicles.

 

There is nothing stopping the DNO undergrounding the HV cable then coming up to a pole mounted transformer then back down again to your house.  You need to get alternative quotes from them for that option to compare the cost of underground cable vs overhead.  Underground has the advantage you can dig all the trenches and lay the ducts and they just have to pull the cable through.

[markc]

Ground transformers are expensive due to the compound or “shed” to house them plus they are much stronger construction.

overhead requires poles but the conductors are much cheaper per metre

[Nickfromwales]

You'll do £40k and then another £40k going properly off grid. Work your best at whittling the cable price down and bite the bullet.

 

you 100% need to get a 3-phase cable in now, as an all-electric house, +PV, +EV or 2x EV will not bode well off a single phase. Get the quote adjusted and see what they come back with, but I would look LONG and HARD before going truly off-grid. Batteries will last 10 years or less,so factor in their decline and demise / recycling / replacement in a 30 year proposal to get some real figures. Space heating will never run off PV unless you've a huge array, huge battery storage, a genny, and an LPG boiler for backup heat input + DHW.

Off grid = multiples of £10k''s and a life enslaved to maintenance and monitoring. No ta. Buy the cable.  

[PaulD]

Thanks for the comments regarding off grid @Nickfromwales I was going to spend some time looking into it ... sounds like Imy time would be better spent pursuing a better priced "on grid" solution.

 

I'm told that over 500m isn't suitable for LV runs but I'm no expert .. thank you to everyone for their comments. It does sound like underground then up to a single pole/transformer, then back down underground for the final LV stretch could be the way to go. Made enquiries with a couple of other providers so will see what they come up with. Had this with Western Power in the past, and ended up going through a company called Connections 2 Energy - https://www.connections2energy.co.uk/

 

@Bonner the non-contestable was £3500 and contestable £37.5K !!

Edited February 9, 2022 by PaulD

[Bonner]

That’s a big chunk! Looks like you are already on with getting alternative quotes from contractors. As others have said, you could break it down into smaller work packages and materials, ie. trenching, cabling, connections etc. This will need you to have an understanding of the specifications/standards and project manage the work but should get the cost down significantly.