UK Do I need three phase or not? Your advice appreciated.

[Spinball]

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.

 

[James]

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.

 

[snowhead]

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.

 

[Spinball]

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.

 

[pc1966]

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.

 

[westward10]

Agreed £4k sounds like a bargain.

 

[nicebutdim]

'About' £4k over the phone, could run into significantly more when/if a firm quote is produced.

 

[Spinball]

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?

 

[timhoward]

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

 

[Spinball]

No

What’s the best case scenario?

 

[SJD]

If the DNO have to dig up the road anyway, quite possibly they will look to see who they can get away with charging it to, e.g. the first customer to ask for 3-phase.

 

[timhoward]

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.

 

[Spinball]

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.

 

[telectrix]

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. .

 

[Spinball]

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. .

View attachment 96541

imagine trying to tow a caravan on one of these!

 

[telectrix]

imagine trying to tow a caravan on one of these!

get jeremy clarkson to tow it.

 

[UNG]

How is it we get a thread like this wanting and expecting the impossible on.......................................................

April 1st

 

[telectrix]

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..

 

[timhoward]

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!

 

[Spinball]

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

 

[pc1966]

So this setup is going to be needed more and more often as we approach 2030.

Load management over the whole system is going to be needed as well, so CT limiting and central reporting/control will, I suspect, become a requirement for any fast charger.

Basically you can have 100+ houses on a 500kVA substation as the normal usage patterns (diversity of load use) means it is not overloaded for any significant time. But the old 'normal' did not include several 7kVA chargers (or more) running for many hours simultaneously on half of the properties!

 

[Spinball]

Load management over the whole system is going to be needed as well, so CT limiting and central reporting/control will, I suspect, become a requirement for any fast charger.

Basically you can have 100+ houses on a 500kVA substation as the normal usage patterns (diversity of load use) means it is not overloaded for any significant time. But the old 'normal' did not include several 7kVA chargers (or more) running for many hours simultaneously on half of the properties!

If those houses have solar, then maybe it won't be so bad, and my plan is to be as 'off grid' as possible with mine, but that doesn't mean that I won't want to charge everything up at some point.

 

[pc1966]

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

3-phase is good for many reasons, just not cheap!

As mentioned above, the assumption for getting 3P in the UK is high load, so you might find it becomes limited due to the local substation's capacity.

I think some EU countries traditionally had 3P to homes but at much lower currents (e.g. 30A per phase) so similar total power to our 100A but more efficient cable use (but more expensive DB/meter/etc). @Lucien Nunes has much more knowledge of that aspect!

 

[pc1966]

If those houses have solar, then maybe it won't be so bad,

Not much use for over-night charging!

and my plan is to be as 'off grid' as possible with mine, but that doesn't mean that I won't want to charge everything up at some point.

It is a good goal, though if you really want to be able to operate in "island mode" (i.e. without grid power at all, even if just during storm damage) there are other concerns.

Mainly you need your own means of earthing (as the DNO's earth cannot be assumed if outage due cables damaged) and also your installation then needs to be able to disconnect on your own earth, which typically means RCD protection on every circuit, as few earth rods are low enough in impedance to allow over-current disconnection like the DNO supply earth normally enables.

Also it means your inverter has to be designed to operate without grid power (not the norm in solar as I think most shut down if grid is lost), and you must have a suitable relay to prevent any power being back-fed in to the faulted grid and possibly killing a DNO worker trying to repair things (a reason for them normally shutting down, along with what might happen when power is restored and maybe not in-phase with the inverter output).

 

[pc1966]

One last thing - if you get anything done by the DNO, unlooping or 3-phase - get an isolator switch fitted at the same time.

Not only will it make any future work on your system easier and quicker, but should you get a PV/battery system that is capable of island mode operations you can test it by switching off the DNO supply for a couple of hours to see that it works, and keeps working on restoring the power...

Test both night and day times, just to be sure PV charging work in island mode and that it still behaves on battery alone, etc.