https://www.bbc.co.uk/news/uk-politics-66900999

<blockquote><cite>Posted By: djh</cite>Interesting discussion on my local socials today about heatpumps, EV chargers and all the rest. One case was a chap who presently uses an oil boiler (no gas) and who looked into a heat pump. He currently has a 60 A connection and was told he needed bigger, so he asked. He has to pay for new overhead cables from the nearest transformer and underground cables in his property. Then because the transformer is fully loaded, he has to buy a new transformer as well. At that point the number of zeros on the bill was somewhat greater than he was comfortable with, so he's getting a new oil boiler. Other commentators mentioned being in listed buildings, meaning restrictions on double glazing, on new radiators, on holes for heat pump pipes etc etc. So lots for Rishi to think about.</blockquote>

How much insulation does he need to put in to drop the heat demand enough that 60A is fine?

Where there's a really quaint old village of picturesque 400 year old houses this approach seems nice although the first off was fairly pricy:

https://www.cambridgeshire.gov.uk/residents/climate-change-energy-and-environment/climate-change-action/low-carbon-energy/community-heating/swaffham-prior-heat-network/about-swaffham-priors-heat-network

WIA, from my experience ( i looked into ground source for my place) suppliers/installers like to work with a significant safety margin in terms of the amount of heat they expect to provide and the electric demands the home as a whole may have, so the homeowner is pushed towards upgrades and improvements as part of the new heating system, without them you start getting caveats from the supplier about performance, no one wants to make significant investment and find it doesn’t work but then finds the upgrades make things totally unviable financially.

I gave up and went with gas, i’ll sit back and wait for the market to evolve and learn what does and does’nt work and look at things again in about 10 years.

As for Sunaks announcement last week, it was really no surprise and pretty much in line with my comments in another thread about the private rented sector.

Currently there’s way too much fresh air between what is technically possible, the countries ability to physically do the work (in terms of suitably trained and experienced companies and workforce) and the ability of the end user to pay for the works ( especially in light of the distortions in the market from the various grants and schemes).

For myself and a good number in my peer group, having enough rainy day money to pay for a new hip (and avoid years of pain and curtailed quality of life, whilst waiting for the nhs to do what they should) is way higher up the list than spending the money chasing net zero.

For me the issue I see, is not if you are going to have so much of a load on a particular premises, ( though I guess the diversity calculation may change negatively) as the capacity of the grid to replace all of the energy that will be required to replace the loss of gas, oil, petrol, diesel etc, that is one heck of a lot of energy that the grid needs to supply. I have grid poles in my fields and SP often come to service equipment. Talking to a supervisor (don't know what level he was) a little while ago he could not see things improving soon. Considerable investment was recognised and needed but waiting for the government to take the initiative. The parent company in Spain was unlikely to invest and his cynical view was after the UK tax payer had paid for the upgrades owner Iberdrola (of which Qatar Investment Authority is a major shareholder) would keep taking the profits. Bit worrying if that is the view of an employee but then he is an UK taxpayer.
We have an 80A supply. When we were building I wanted our existing overhead supply to go underground. The surveyor suggested as we had 3P going to our farm outbuildings we could have 3P to the house. (Forgot the cost but it was a lot) My reply was that the idea of doing the work we planned was to decrease our energy consumption (which we have) not to use more.

IMO diversifying a households load to avoid power hungry (even if intermittent) devices coming on together to avoid overloading the main fuse is a big ask for most households.
People will want to switch on what they want when they want it. Topping up the EV nightly on a granny charger is going to be too much hassle, once a week plug it in when you get home from work to the 22A charger, go inside, put on the washing machine and the electric hob for supper - all done by 21:00 and never mind the grid. I'm not sure that financial incentives will change things much but I don't know what would.

Posted By: revorFor me the issue I see, is not if you are going to have so much of a load on a particular premises

But that issue is just as real as the bigger issue I believe. There are a lot of people who as things are can't go all electric without an upgrade to the cables supplying them. So either the rules on how systems are sized need to change or maybe the financing rules need to change, or something else needs to change, but at present there's a real problem.

And sure there'll be a problem supplying enough power overall as well. The privatised infrastructure is a dumb idea.

As part of Rishi's speech he announced new powers to fast track grid infrastructure projects through planning (which I guess are aimed at your part of the country!).

Nothing wrong with 40A cookers, I have one on a 32A MCB which has never tripped, because the rings and oven all modulate*. Was just an example, to show why the 60A cutout man was worried about the wrong appliance, if he thinks he doesn't have enough amps for a heatpump.

Most people don't commute long distance every day any more, average UK car does 20 miles a day (~5kWh). Plenty of time to fit that round the heating in the off-peak period.

Actually I should say "off-peak" not "overnight", because cheapest electricity prices have frequently been mid afternoons this year, not just overnight. Today's cheapest was at 1430.(edit: and it was greenest in the afternoon, lots of PV and wind, >90% non-fossil electricity)

*Edit to add - and because fuses/MCBs/cables have a time-adjusted current rating. A 60A main fuse can carry 70-90A for long enough to cook the dinner and charge up the car. Graphs in the various BS docs.

Mike1 mentioned on the similar thread that 30A supplies are common in France (60A max) and they are installing 10x more heatpumps than in the UK.

Physics is the same on both sides of the channel, so istm the problem here is psychology!

Here's what Mike1 said

"[a 60amp fuse is] a typical connection for an electrically heated house in France - the maximum monophase connection offered, I think. For those on gas, it's typically 30A. Around 70% of all domestic properties, including apartments, have a 30A connection.

That's low compared to the UK for 2 reasons:
- the power chosen determines the standing charge, so there's an incentive to keep it low (a 60A connection costs in the region of €19/month, 30A around €12.50, down to €9.25 for the minimum 15A supply)
- a load-shedder can be fitted to the consumer unit that temporarily disconnects one or more selected low-priority loads (water heating, central heating, washing machine, etc.) if the total load approaches the maximum - for example while fully using an electric hob.”

http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303297#Comment_303297