Three Phase requirement for "high usage"

anon_ymous

If you've got an EV, and a heat pump I think that'd be high usage enough 

It seems like Ofgem at least want the network operates to do this for free and have the costs socialised via the standing charge, which makes sense when apparently one in three houses need it

https://www.homebuilding.co.uk/news/one-in-three-homes-might-need-electricity-upgrade-for-heat-pumps-to-work

Martyn1981

I couldn't work out if the article is really suggesting 3phase for 1 in 3 homes, as it seems to suggest upgrades, but 'imply' 3phase? At one point it mentions a main fuse upgrade to 80A or 100A, which may actually be the 'upgrade' for most properties. When we had the EV charger installed our main fuse box was upgraded to 100A, but the fuse was only upgraded from 60A to 80A.

But with regard to heatpump and BEV's, I'd have thought most properties would be OK with 80A or 100A single phase. Assuming your heatpump provides DHW, then even a large 16kW unit, pulling 4kW of load, is still less than a power shower with 7-11kW of load.

Not saying everyone will be fine, but one EV charger at night pulling 7kW, and a 10-12kW heatpump pulling another 3kW(?), is still 'only' about 44A.

But, I wonder about two EV chargers, and whether that, plus a HP, would be pushing the envelope. Plus, if we want to future proof, and allow BEV charging at ~12kW, then maybe 3phase for newbuilds?

My sister upgraded her property to 3phase two years ago, and it cost about £2k, but there was a 3phase supply already at the pole supplying the property, about 30m to 40m away.

Screwdriva

Depends on the size of the heat pump, the property heat loss and the time of charging the EV. In most cases, a 100A fuse upgrade would be sufficient. 

anon_ymous

Screwdriva said:

Depends on the size of the heat pump, the property heat loss and the time of charging the EV. In most cases, a 100A fuse upgrade would be sufficient. 

Ah so not quite "1 in 3" then but could be an issue if you've got two chargers 

Qyburn

Just to drop a random comment, some properties around here, including two of the village halls are on two phase supplies. That proved a bit of a head scratcher when getting prices and specifications for generstor bsckup.

It was some special Northern Scottish thing way back. Three phase wasn't offered, and there were even two phase machines in commercial workshops. 

Ectophile

If you actually need a three phase 100A supply, you probably won't be able to afford your electricity bills.  100A on one phase works out about £7.50 per hour on standard rate.  So about £22.50 per hour if you're using all three phases to the maximum.

QrizB

It's probably also worth mentioning that, for many urban or suburban consumers, all three phases will be present on poles (or underground) on their street.

Moving from a single phase supply to three phase will simply mean replacing the incoming cable with a four-core one, fitting a new cut-out and a new meter.

It's rural properties where switching to three-phase might cause more trouble. My sister has a GSHP (although seems to take little interest in its workings) and enquired about three-phase. She was told by the DNO that there wasn't any to be had in her hamlet and it would need some sort of substation upgrade!