3 Phase Supply Conversion - Needed or OTT

[tododo]

Hi all
Im in the process of getting a new drive layed. Its a long story but desperately waiting for the guy to come back any time now. Anyway recently been looking at plugin hybrids as the missus needs a new car and that led on to upgrading the supply comming into the house and some fast chargers need 3 phase

Im new to all this so please correct me - havnt got a clue really

I know a colleague in work recently had a 3 phase put in (and I did wonder why when he mentioned it) at home at a cost of around 6K. I havent got that money for it and right now I have no need of three phase at all but as this drive is totally up..... now would be the time to lay a conduit possibly just in case

I dont know - would that be a good idea do you think. I think the duct has to be 450mm down but I am not 100% sure - national grid wernt that great when I called them earlier

I dont fancy digging another trench but if Im going to do it now would be a good time I suppose or is it pointless in the home environment
Thanks for any advice

 

[plugwash]

Single phase AC charging in Europe (it seems to go higher in the USA) seems to have a max of 7kW . Three phase charging can support 11kW or 22kW charging modes.

However, many cars don't support these modes, a plugin hybrid is especially unlikely to do so. Also even if the car does support it, for domestic charging there is little point. 7kW is enough to fully charge almost any electric passenger car overnight.

 

[JohnW2]

I know a colleague in work recently had a 3 phase put in (and I did wonder why when he mentioned it) at home at a cost of around 6K. I havent got that money for it and right now I have no need of three phase at all but as this drive is totally up..... now would be the time to lay a conduit possibly just in case

It's not that many people need ';three phases' but, rather, that DNOs generally (always?) provide a maximum of a 100A single phase supply -so people get 3-phase if they 'need' more than 100A. That is going to become increasingly common because of EV charging - if coupled with electric cooking and electric showers (plus 'the usual' loads) that can easily add up to a 'maximum peak demand' above 100A

.... right now I have no need of three phase at all but as this drive is totally up..... now would be the time to lay a conduit possibly just in case

Are you sure that the DNO would be prepared to use your conduit/duct in the future?

Kind Regards, John

 

[plugwash]

It's not that many people need ';three phases' but, rather, that DNOs generally (always?) provide a maximum of a 100A single phase supply -so people get 3-phase if they 'need' more than 100A. That is going to become increasingly common because of EV charging - if coupled with electric cooking and electric showers (plus 'the usual' loads) that can easily add up to a 'maximum peak demand' above 100A

The usual way round that is EV chargers with a current transformer that monitors power draw from the grid and reduces or suspends EV charging as needed to keep the overall draw from the grid within limits.

Electric cookers and showers can draw a lot of power, but usually not for very long.

 

[tododo]

Yes Im not sure if they would use my conduit in future your correct - no idea really. I assume they would if I take enough photos but then again the spec may change if the time comes that I do need to think about three phase
The plugin hybrid doesnt need it right now - thats correct, but Im just thinking about the future really and if it would be a good idea to put a conduit in - never straight forward is it!

 

[JohnW2]

The usual way round that is EV chargers with a current transformer that monitors power draw from the grid and reduces or suspends EV charging as needed to keep the overall draw from the grid within limits.

Yes, I know that, but if people have other significant high power loads, they might not be too happy with their EV charging being 'slowed down'as a consequence.

Electric cookers and showers can draw a lot of power, but usually not for very long.

Whilst that's true, DNOs seem to be concerned about "maximum peak (i.e. instantaneous) demand", with minimal allowance for 'time diversity".

If I tell SSE's 'demand calculator' that I have electric cooking, one shower and one 7kW'EV charger is estimates my "Maximum Peak Demand" as 105.44A and, as a consequence, says that a single-phase supply is not adequate and that I should contact them to discuss the possibility of a split-phase or 3-phase supply.

 

[EFLImpudence]

Why would anyone consider buying an EV before actually having to have one?

 

[tododo]

I defo dont want a 100% EV thats for sure but it looks like everything is heading that way regardless....its only becase the drive is up and my colleague has some conduit / tape etc left over that I can have!

 

[Adam_151]

WHat you should do is confirm whether your supply is looped, i.e. a cable off the street main goes to one house and on to another, it was quite common on new build developments in one era 60s/70s? . But these days the DNO are supposed to unloop you for free if you are planning on having an EVSE, it would be sensible to confirm if you are in need of that, before the new driveway goes down.

Its becomming more common for cars to have a charger on board that will pull 11kw from a three phase supply if available (3x16A), not many can make use of the full 22kw (think the Zoe might be able to), and some will still only have a single phase charger that will only draw 7kw. But you don't need to charge at more than 7kw at home unless you have got a weird use case, but the ability to use all three phases is usful on workplace/destination charging sites, means things don't get so unbalanced quite so easily

 

[tododo]

House is from 1930s so no idea what that could be! I did call national grid today but they werent very good I may try a written query instead - and ask what they require in terms of conduit and tape and where I can come into the house - thanks all worth asking and Ive learned a bit about electricity demand on these evs too - so all good

 

[JohnW2]

Why would anyone consider buying an EV before actually having to have one?

I don't think anyone has suggested that,have they?

However,as for you question, I gather that many Estate Agents are now telling sellers that having an EV charger can appreciably increase the value of their property - so, if that is true, it might be one answer to your question!

 

[bsr]

I did call national grid today but they werent very good

Where do you live? In most of the country National Grid only do transmission so unless you want a run of 400kv pylons up the drive they won't help.

 

[SUNRAY]

It's not that many people need ';three phases' but, rather, that DNOs generally (always?) provide a maximum of a 100A single phase supply -so people get 3-phase if they 'need' more than 100A. That is going to become increasingly common because of EV charging - if coupled with electric cooking and electric showers (plus 'the usual' loads) that can easily add up to a 'maximum peak demand' above 100A

Are you sure that the DNO would be prepared to use your conduit/duct in the future?

Kind Regards, John

If it's in the right place and photos of it in the open trench? Yes

Speak to them now and ask for an estimate, discuss it when they come to do the survey.

 

[Adam_151]

Where do you live? In most of the country National Grid only do transmission so unless you want a run of 400kv pylons up the drive they won't help.

WPD who look after the former Midlands, East Midlands, South Western and South Wales Electricity board areas, have in the last few years been absorbed into national grid and been rebranded https://www.nationalgrid.com/electr...-power-distribution-joins-national-grid-group