Discuss Do I need three phase or not? Your advice appreciated. in the UK Electrical Forum area at ElectriciansForums.net

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Hello folks.
I am about to complete on a (detached) house purchase and I want to ask your advice whether to have three phase connected to the house and possibly whether I can have it connected for free.
I plan to have two Zappy EV chargers installed with them both charging at the same time overnight when electricity is cheaper.
I also want solar panels and a battery solution and I could potentially be charging the battery at night as well.
I know that there are load balancers for EV charging, but it’s probable that I will want to charge both EVs at the same time in the 4 hour Octopus Go cheaper tariff window.
I am thinking that I probably need three phase to cope with this load. Have I got this right?

Also the house is looped.
What I am hoping is that an application to install the two car chargers and battery will mean that the DNO consider that I will need three-phase and will install that FOC while delooping the house. What, in your experience, are the chances of this happening?

Many thanks in advance for your help.

Hello moderators. Please move this thread to a more appropriate form if this is not the right place for it.
 
Free of charge supply upgrades are only considered between 08.35 and 08.52 on the morning of April 1st, so if you have not had your application accepted this morning, you have to wait until next year.
 
There's no guarantee that you'll even be able to have 3 phase, it may not be laid in your road / street and even if it is there may not be enough spare capacity without you having to pay possibly thousands to have it upgraded or installed.
You'll need to enquire with the DNO to see what's available.

It's most unlikely you'll get it cheap, let alone free.
 
There's no guarantee that you'll even be able to have 3 phase, it may not be laid in your road / street and even if it is there may not be enough spare capacity without you having to pay possibly thousands to have it upgraded or installed.
You'll need to enquire with the DNO to see what's available.

It's most unlikely you'll get it cheap, let alone free.
I called my DNO to discuss it (that's how I know the property is looped) and he said that it would cost about £4k to upgrade to 3 phase. I'm trying to avoid that expense.
 
I called my DNO to discuss it (that's how I know the property is looped) and he said that it would cost about £4k to upgrade to 3 phase. I'm trying to avoid that expense.
That is actually cheaper than I feared!

If you plan EV fast charges and/or large heat-pump based building heating for the future then 3-phase really is the way to go, but it will cost you obviously.
 
Is it possible that, when the company installing the system (12kw solar, 20kw batteries, 2 Zappis and an Eddi) apply to the DNO, that the DNO will look at the system, and agree that we need delooping and 3-phase and decide to do both FOC? Or at least discounted since they are digging up the road/drive anyway?
 
Is it possible that, when the company installing the system (12kw solar, 20kw batteries, 2 Zappis and an Eddi) apply to the DNO, that the DNO will look at the system, and agree that we need delooping and 3-phase and decide to do both FOC? Or at least discounted since they are digging up the road/drive anyway?
No
 
3 Phase doesn't ever come free or even cheap. A site I worked at had a quote for £15K for a 3 phase 200A supply. They dithered a bit, and in the meantime another neighbouring site had an install completed. By the time they decided to accept the quote, the transformer capacity was gone and it turned into a >£30k quote (and didn't happen)
What’s the best case scenario?
You might get un-looped for free but you'll never get 3 phase for free.
If you can actually get 3 phase for £4k I'd snap their hand off - like others have said, I'm afraid I have doubt's that is a real-world quote, it sounds like the sales/marketing quote before the engineering survey.

I'm being blunt, but unless you have oodles of spare cash you'll probably need to scale back your ambitions a bit.
I'd probably get unlooped and (presumably) upgraded to 100A if possible, get the two Zappi's in with load monitoring, and start with simple PV without a battery.
 
3 Phase doesn't ever come free or even cheap. A site I worked at had a quote for £15K for a 3 phase 200A supply. They dithered a bit, and in the meantime another neighbouring site had an install completed. By the time they decided to accept the quote, the transformer capacity was gone and it turned into a >£30k quote (and didn't happen)

You might get un-looped for free but you'll never get 3 phase for free.
If you can actually get 3 phase for £4k I'd snap their hand off - like others have said, I'm afraid I have doubt's that is a real-world quote, it sounds like the sales/marketing quote before the engineering survey.

I'm being blunt, but unless you have oodles of spare cash you'll probably need to scale back your ambitions a bit.
I'd probably get unlooped and (presumably) upgraded to 100A if possible, get the two Zappi's in with load monitoring, and start with simple PV without a battery.
Unlooping 100% happens for free as the DNO has an obligation to connect each residence with it's own supply.
I am purchasing the house and have set money aside for this.
I've done solar in 2015 plus zappi and eddi when they first came out in the UK (Lee Sutton visited the site for a video), so I'm reasonably informed on that area. 16 x 400 watt panels on the E/W main roof plus 10-16 on the south-facing double garage (which I'm extending) plus, possibly 3 or 4 x 5kw Huawei batteries with the aim of minimising electricity (and some gas) expenses.

If load balancing means I can't charge both cars simultaneously, then it's not appropriate for our use.
 
I'd probably get unlooped and (presumably) upgraded to 100A if possible, get the two Zappi's in with load monitoring, and start with simple PV without a battery.

and trade in the cars for a couple of these. <5A charge current.,off a general 13A socket. 🤣🤣🤣.

1648886120973.png
 
cost would depend on how much red/yellow/blue/black multicore DNO has in stock, forgotten in some shed on a site everyone's forgotten about..
 
If load balancing means I can't charge both cars simultaneously, then it's not appropriate for our use.
I don't own an EV and you are obviously better informed than me about your charging requirements, but I'm surprised if charging at 32 amps it would apparently take all night to charge both cars simultaneously?
Load monitoring simply means the charger has a setting for max demand of the supply and stops charging the car if the normal usage exceeds this. It's more typically used on 60amp supplies.
With an 100A supply I would have thought one charger could be un-capped and be part of the max demand calculation and the 2nd one set to only charge if the overall demand was under say 60 amps. I would therefore expect it to be possible to run both chargers most of the time.
I'm far from an EV charging expert though and others might correct me!
 
I don't own an EV and you are obviously better informed than me about your charging requirements, but I'm surprised if charging at 32 amps it would apparently take all night to charge both cars simultaneously?
Load monitoring simply means the charger has a setting for max demand of the supply and stops charging the car if the normal usage exceeds this. It's more typically used on 60amp supplies.
With an 100A supply I would have thought one charger could be un-capped and be part of the max demand calculation and the 2nd one set to only charge if the overall demand was under say 60 amps. I would therefore expect it to be possible to run both chargers most of the time.
I'm far from an EV charging expert though and others might correct me!
Owned an EV since 2017, but I'm pretty much clueless in electrical stuff (unlike my Dad who served his apprenticeship with the MEB, but is no longer with us), but I'm guessing more households with two cars will be switching to EVs, most with batteries which are 50kw+, so expect to want to charge both at night occasionally if not regularly.
Worse case scenario, that's two cars for 5+ hours (on average assuming charging from, say 20 to 80%) at 7kwh.
So this setup is going to be needed more and more often as we approach 2030.

Then if I want to charge the battery as well, that's even more load. Don't know what rate a battery will charge. Don't know much about batteries yet.
If people are using the Octopus Go Tariff with cheaper electricity between 00:30 and 04:30, then they are going to want to pump as much into both cars and the batteries as possible in this 4 hour window.

All I know is o-level Physics. W=A x V. That's pretty much it.
I'm asking you guys as I have no clue what the procedures are for upgrading to 3-phase and I'm an optimist. Don't beat me up for that :)
 
Last edited:

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