When does 3 phase supply become 230V in domestic consumer unit?

[HappyHippyDad]

I went along this morning to quote for an EVCP install.

I thought it was a domestic house but it was a B@B. It has a 3 phase supply. I always pass on commercial or 3 phase as it is outside of my remit. However, I am toying with the idea of fitting this EVCP IF I can fit it from a single phase supply.

I am unsure where to take power from. Usually I would either split the meter tails or use a spare way in the CU. I could use a spare way in an existing CU at the property but it may be better to take power from somewhere in the meter room. However, I am unsure where it is 230V and where it is 400V.

You can see in the pictures there is a 3 phase cut out, to meter, to isolator, to Henly blocks, to separate meters, then to switched fuses, then off to each area. Where would I split the tails? Where is it 230V? It must be 230V coming from the switched fuse (B) going to the single phase consumer unit in the annex (because it's a single phase board). But, another switched fuse (A) goes off to the main house which has a 3 phase board. There is no difference with regards the cables leading up to either of these switched fuses, (i.e they both have a separate meter and a single Line and neutral going to them), so how is one of them 230V and the other 400v?

 

[Gavin John Hyde]

I know you say 3 phase is iut of your remit but all new supplies from WPD are going to be 3 phase as standard from now on.
Could be a chance grow your skillset.
Assuming there is capacity on the supply (check with dno) even if offered 22kw few cars charge above 7kw on ac anyway
Then fit a few.henley blocks after the isolation switch by the meter and run a small consumer unit for the ev.
Main switch plus mcb will do a 22kw zappi. Can fit 3 ct clamps to monitor the load.
Depending in cable route you may need to factor in rcd protection.

 

[Julie.]

I know you say 3 phase is iut of your remit but all new supplies from WPD are going to be 3 phase as standard from now on.
Could be a chance grow your skillset.
Assuming there is capacity on the supply (check with dno) even if offered 22kw few cars charge above 7kw on ac anyway
Then fit a few.henley blocks after the isolation switch by the meter and run a small consumer unit for the ev.
Main switch plus mcb will do a 22kw zappi. Can fit 3 ct clamps to monitor the load.
Depending in cable route you may need to factor in rcd protection.

Agree, however we are getting more and more cars able to take in excess of 7.4kW, just a year ago there were very very few, but within the last year alone Renault, BMW, telsa and BYD have all introduced 11 or 22kW chargers within their cars.

Over the short time EVs have developed they have gone as standard from 2.3kW through 3.6kW, 7.4kW, and now 22kW.

I would expect within the next year or so pretty much every new EV will have the capability of greater than 7.4kW.

They have to really, because as smart control starts operating, it will shut down for periods, so EVs won't be able to rely on low rates for long times.

 

[brianmoooore]

I know you say 3 phase is iut of your remit but all new supplies from WPD are going to be 3 phase as standard from now on.
Could be a chance grow your skillset.

In spite of having been in the business for over half a century, working on mainly farm and rural domestic, I can count the number of clients I've had with three phase supplies on the fingers of my hands, possibly one hand. Until a few years ago, when the main 11kV trunk had a third wire added to it, I lived in the middle of about a hundred square miles of three phase desert. To this day, most of the branches off of the trunk, including my own, are only two wire.

With regards to the multiple meters in the property in question, I suspect this is similar to what I have with my own holiday cottages. Under normal operation, with 'tenancies' in the various properties being either one or two weeks, the sub meters aren't read, with the landlord picking up the tab for the whole supply, but occasionally you get a longer tenancy, such as a winter let, or, as I had once, someone moving to the area for three months to search for and buy a property, and then the sub meters are read (or card meters programmed 'on', in my case).
I also have sub meters around the place for the hot tubs, industrial tumble drier and the EV point, just so I can keep tabs on what these things cost to run.
For these reasons, I'd ensure that the EV charger goes onto its own meter,whether single or three phase.

 

[Zerax]

However, it does sound as though a 3 phase EVCP would be a better option for the owner.

That partly depends on if the intended vehicle has a 3P charger on-board... mine doesn't But then I guess there's no harm in making it "future proof".

 

[Mikegh]

What do you mean? What's crude about it? You've got to split somewhere.
All single phase supplies originate from 3 phase.
How do you connect a 3ph load when only single is required.
Any block of flats, for instance, is fed similarly, with single phase to each property. Balancing phases is a job for the designer.
Obviously, millions of single phase circuits come from 3 phase boards.
What's wrong with a single phase board in a factory, say, where required?

I was probably generalizing and I take your points

In the factory situation you generally distribute in 3P

The concern where you split at the origin is that the loads are unbalanced .That board in the pic looks well loaded.

 

[Gavin John Hyde]

Agree, however we are getting more and more cars able to take in excess of 7.4kW, just a year ago there were very very few, but within the last year alone Renault, BMW, telsa and BYD have all introduced 11 or 22kW chargers within their cars.

Over the short time EVs have developed they have gone as standard from 2.3kW through 3.6kW, 7.4kW, and now 22kW.

I would expect within the next year or so pretty much every new EV will have the capability of greater than 7.4kW.

They have to really, because as smart control starts operating, it will shut down for periods, so EVs won't be able to rely on low rates for long times.

Agree with you, a lot of what we are fitting now, will within 18-24 months be out of date. My Kona EV has 11 kw charge function on board. My charger on wall is 7kw.
It reminds me of the growth in computer specs in the late 90s, early 2000s, memory, processor speed and storage were growing at ever quicker rates.

Several years from now I think there will be a much better OCCP and communication between different brands, the grid and smart functionality in general. coupled with links to the cloud, you will I think see major advances in the way chargers integrate with the grid at local level according to demand.

 

[westward10]

This is how a triple pole board is converted to single pole operation. Manufacturers vary as to where the link is fitted.

 

[ipf]

This is how a triple pole board is converted to single pole operation. Manufacturers vary as to where the link is fitted.View attachment 90354

Don't think I'd leave it like that, though.....?

 

[westward10]

Don't think I'd leave it like that, though.....?

It has a shroud over it but I took if off for the pic, live of course.

 

[ipf]

It has a shroud over it but I took if off for the pic, live of course.

wink, wink! As if.........