Green Building Forum - 3 phase electrics Sun, 28 Jun 2026 10:41:27 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305175#Comment_305175 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305175#Comment_305175 Sun, 04 Feb 2024 09:48:06 +0000 revor 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305178#Comment_305178 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305178#Comment_305178 Sun, 04 Feb 2024 12:05:22 +0000 djh Posted By: revoroops looks like it did not add.maybe it was too large?

Posted By: revorHaving 3P I understand can be dangerous if you happen to mix phases by inappropriate use of extension leads or modify wiring in any way.
Indeed, which is why we were surprised to find such a basic error.]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305179#Comment_305179 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305179#Comment_305179 Sun, 04 Feb 2024 12:08:18 +0000 djh https://www.neff-home.com/ie/service/support/induction-hobs/induction-cooker-installation

Elsewhere I saw mention that it can be difficult to find 3-phase isolators that are attractive in a domestic setting?]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305349#Comment_305349 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305349#Comment_305349 Mon, 19 Feb 2024 15:12:37 +0000 revor They offered to do 3P to the house about 35 metres of cable think was about £3k (2010) and that was with 3P on site. I declined because my intention was to use less power not more.

https://www.homebuilding.co.uk/news/octopus-and-national-grid-join-forces-to-upgrade-homes-to-three-phase-electric-as-part-of-heat-pump-and-ev-charger-rollout]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305351#Comment_305351 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305351#Comment_305351 Mon, 19 Feb 2024 16:44:27 +0000 djh
Secondly how is a heat pump installer going to upgrade a 'fuse' to three phase? Surely that involves digging up the road and connecting two more phases, not just changing a fuse? I'd have thought there aren't many heat pump installers that are certified for that, and it wouldn't make much sense since there's very little overlap between the two skill sets.

And third, how does putting lots of houses on to three phase benefit the network? It's the total kW or total A that matters. It doesn't matter whether there's 300 single phase connections using 25 kW each, or 300 three phase connections using 25 kW each. The total down each wire is going to be the same beyond half a dozen houses or so.]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305353#Comment_305353 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305353#Comment_305353 Mon, 19 Feb 2024 17:55:29 +0000 Dominic Cooney Posted By: djhwhy is three-phase needed?

Is it so that large, poorly insulated houses can switch over to heat pumps?
When I looked in to GSHP for our house, Kensa specified a 14kW model, which was the largest single-phase one they did (at the time, just having a quick look on their website today they do a 13kW and a 17kW in single phase, then a 15kW in 3-Phase)
So presumably any larger than this would need 3-Phase.]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305355#Comment_305355 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305355#Comment_305355 Mon, 19 Feb 2024 22:17:29 +0000 WillInAberdeen
The deal between Octopus and NG has been widely reported but no other reports I saw have suggested that they will install 3 phase.

The deal seems to be that, if a customer needs their existing single phase fuse upgraded say 60A to 80A, then Octopus will do that themselves while they are on site, instead of waiting weeks for NG to send someone else out to do it.

They also had their range of heatpumps pre-approved by NG, so NG don't have to assess each application individually, saving more weeks.

https://www.edie.net/national-grid-moves-to-speed-heat-pump-and-solar-panel-installations/

A typical 16kW heatpump has a 32A MCB but draws 20A max, about half of an electric shower. So nowhere near needing 3 phase in this country.

But as Peter mentioned, many countries wouldn't allow that. Heatpumps are made from parts that are sold in many countries, so have to comply with everyone's rules, you don't really get >16kW+ heatpump compressors made exclusively for the UK market.]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305359#Comment_305359 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305359#Comment_305359 Tue, 20 Feb 2024 08:17:20 +0000 Artiglio
When i bought my place ( old listed barn/oast) , i made a few enquiries regarding heat pumps both ground and air sourced. The companies that got back to me (3) all said i’d need 3 phase on the basis of the buildings levels of insulation at that point ( basically zero) they wouldn’t take into account my intended levels of insulation. They seemed to think i needed 25kw of heat.
I ended up fitting an 18kw system boiler that so far keeps the place cosy running at 50-55 degrees. Hopefully by time i eventually finish this will be reduced/ boiler run times are less.

I then enquired about 3 phase supply, the estimate for that was 12k, of which 5k was for traffic management on a residential side road. House has been plumbed / wired with nod towards an eventual heatpump, cables run will be able to supply 40 amps max if needed.]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305364#Comment_305364 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305364#Comment_305364 Tue, 20 Feb 2024 10:08:37 +0000 WillInAberdeen
https://www.kensaheatpumps.com/installer/heat-pumps-and-single-phase-electricity/

TLDR: the European market for large heatpump compressors is 3-phase. They can use electronics to convert a UK 1-ph supply into a waveform to run a larger 3ph compressor. Or they can simply put two smaller 1ph compressors in the heatpump, to give double the output.]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305368#Comment_305368 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305368#Comment_305368 Tue, 20 Feb 2024 16:29:18 +0000 djh Posted By: ArtiglioI then enquired about 3 phase supply, the estimate for that was 12k, of which 5k was for traffic management on a residential side road.Was that the DNO's price? I believe it's contestable work?]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305369#Comment_305369 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305369#Comment_305369 Tue, 20 Feb 2024 16:32:45 +0000 djh Posted By: WillInAberdeenKensa do/did a 24kW single phase heatpump - a write-up here ...Thanks for that :bigsmile: Looking at the other articles in the magazine I see in https://www.acrjournal.uk/heat-pumps/airsourceheatpumps-a-reality-check/ something I haven't heard before:

"The real issue that has been ignored and will prove an expensive cost to the homeowner within a relatively short time, is that all the systems fitted now but containing R32 refrigerant will need replacing in under ten years because the ‘F Gas’ refrigerants are being phased out by 2030 and this equipment is not suitable electrically to be retrofitted due to the flammability of the replacement natural refrigerant alternatives."

If that's true then as far as I'm concerned that's a real killer for any consideration of an R32 heat pump. :devil:]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305375#Comment_305375 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305375#Comment_305375 Wed, 21 Feb 2024 09:02:35 +0000 WillInAberdeen
The legislation going through the EU at the moment is to ban manufacturers from launching new HFC systems in the EU after 2027 (monoblock) and 2035 (split system), but there's no ban on using existing products until 2050, and no indication if UK will follow suit.

You don't have to look far in the internet to find this kind of shouting-at-clouds, even on previously 'reliable' sources. R4 You and Yours did a piece on heatpumps recently and saw fit to invite the gas industry's lobby group to provide their expert advisor - unsurprisingly he advised all the callers to keep on burning gas! And if you read the EV articles in a certain longstanding national newspaper, you'd understand why it has just been bought by a petrostate. It's the post-truth era now.

As you said, this sowing-doubt stuff has real-world consequences, because it kills off people considering the transition.]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305381#Comment_305381 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305381#Comment_305381 Wed, 21 Feb 2024 09:47:16 +0000 WillInAberdeen
https://www.consilium.europa.eu/en/press/press-releases/2023/10/05/fluorinated-gases-and-ozone-depleting-substances-council-and-parliament-reach-agreement/


Incidentally, there are proposals to ban PFAS "forever chemicals" in the EU, which will include the R1234 now used in nearly all car aircon systems. The legislation will work through over a number of years and existing cars will not be affected, but new car models will eventually switch over to something else. So don't let that kill any consideration of buying a current model of car!

https://r744.com/volkswagen-plans-to-convert-all-bev-models-to-r744-by-2030/]]> 3 phase electrics https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305383#Comment_305383 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18069&Focus=305383#Comment_305383 Wed, 21 Feb 2024 09:51:39 +0000 Artiglio Depending on finances, i may look into it once again before the drive is done ( as this is the last point a new incoming cable would be practical) but the 3 phase head has to go in an external cabinet and that would mean dealing with the conservation officer and getting listed building consent. The thought of the latter alone is enough to make me not even try.]]>