Upgrading house to 3 phase supply

Mike1983

Mike1983

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Hi all

has anyone here upgraded their incoming electric to a 3 phase supply? I’m thinking of doing this at the same time as renewing my driveway to avoid digging up in the future for a car charger, induction boiler etc.

In doing this, would you NEED to do anything with the existing consumer unit (I.e to balance loads across 3 phases) or is this just a ‘nice to have’?

I’m ideally thinking of upgrading to 3 phase, having 1x phase for the house without having to change the existing consumer unit or wiring, 1x phase for the garage (future car charger) and 1x unused but I’m guessing I’ve not understood / oversimplified things.

Any thoughts and advice appreciated!

thanks
 

Graetzbridge

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Mike1983 said:
Hi all

has anyone here upgraded their incoming electric to a 3 phase supply? I’m thinking of doing this at the same time as renewing my driveway to avoid digging up in the future for a car charger, induction boiler etc.

In doing this, would you NEED to do anything with the existing consumer unit (I.e to balance loads across 3 phases) or is this just a ‘nice to have’?

I’m ideally thinking of upgrading to 3 phase, having 1x phase for the house without having to change the existing consumer unit or wiring, 1x phase for the garage (future car charger) and 1x unused but I’m guessing I’ve not understood / oversimplified things.

Any thoughts and advice appreciated!

thanks
Click to expand...
In domestic residences the consumer unit is usually single phase. They don't do single phase units.
 

Adam_151

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Its overkill, possible but will be a headache, you'd need to co-orinate the DNO (to put a three phase supply in), your supplier (to get them to get their meter operator to fit a three phase meter) and yoru electrician to make the necessary alterations to your installation.

Bear in mind that if the supply is in a reccessed meter box, then you'd need a larger one for a three phase supply. If just on wall then more space would have to be made available for the supply. You'd then need space the other side (or above if already indoors) for whatever equipment you need on your side, whether that is a 3ph DB, or a group of switchfuses, etc
if I was doing it, I'd take three phase into the garage, allows you to have a three phase charge point, and also gives scope for three phase equipment.

But its a lot of hasle and expense for limited gains, personnaly you'd be better off just making sure you don't have a looped supply (where the supply goes to the head in one property and out the bottom to another property - quite common on estates built 50 odd years ago), if you do have a looped supply, and are planning on a charge point, I believe the DNO are supposed to remove the looped arrangement at their cost

TLDR: You could, but it would be a hastle to arrange, and the gains are limited for most people
 

Mike1983

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Adam_151 said:
Its overkill, possible but will be a headache, you'd need to co-orinate the DNO (to put a three phase supply in), your supplier (to get them to get their meter operator to fit a three phase meter) and yoru electrician to make the necessary alterations to your installation.

…..

TLDR: You could, but it would be a hastle to arrange, and the gains are limited for most people
Click to expand...

thank you all.

The above point ‘your electrician to make the necessary alterations’ is the main part of my uncertainty. I’m happy with doing anything in the external meter box, even putting a bigger cabinet in for the larger meter and any ancillaries. The problem Id have though is if it needs any new wiring to my existing consumer unit or a change to the board itself as it’s all in a nicely finished room.

I’ve sent a query to the DNO already to see their costs and info but they obviously will not comment on the downstream side.

There’s no sign of it being a ‘looped’ supply in my meter box at least, it’s an approx 30 year old house. There’s just a single incoming terminated supply.

I get that this maybe considered potentially overkill but as a household that’ll likely have 4x electric vehicles in about 12 years time it would majorly hack me off if I find I need to dig up my driveway to service them. Guessing gas boilers will also be phased out in the future too so I’m trying to cater for the need for an electric one too.

Doing some research on EV charging there’s a fair few sites recommending upgrade to potentially service 22kW chargers so trying to do a bit of future proofing as best as possible.

ta
 

soundb0y

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Im considering running a new line to put 3 phase in so I can potentially install an electric boiler.
Probably a bit simpler doing it on the farm and just running cable across half of a field.
 

gary996

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Its a simple job.
Change board to 3 phase and balance original circuits over the 3 phases.
Try not to get 3 phase into a light switch or close proximity to another phase
Get DNO to fit new 3phase supply (will cost more standing charge)
Voila all done
 

Mike1983

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gary996 said:
Its a simple job.
Change board to 3 phase and balance original circuits over the 3 phases.
Try not to get 3 phase into a light switch or close proximity to another phase
Get DNO to fit new 3phase supply (will cost more standing charge)
Voila all done
Click to expand...

You sound pretty clued up.

Do you happen to know if step 1 is a necessity or could I simply just wire the consumer unit tails to just one of the 3 phases? This would be to avoid quite a lot of disruption in having to run new tails to a new consumer unit which would be quite a challenge in my house.

thanks
 

gazref

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Mike1983 said:
Based on current tech and 1x vehicle? Yes.

in the future with a household of vehicles and other electric needs. I doubt it.
Click to expand...

How many people empty an ev in 1 day though? Average ev does 200miles on a charge and you need what 8-9hrs to charge an average car 0% to 100% ?
Reckon at most you'd need a charge every 3-4 days.

Phase 3 at home is overkill for ev needs imo. Work place? ok now the costs aren't so out of whack .
 

norm

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Do the electricity board tap into the other 2 phases at the nearest point and feed that back to the property, or does it require a feed from the substation? It sounds like it would be rather costly either way routing new cables in a residential setting.
 

BigBoy

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It all depends on what feeds your property.

I work for a supplier as a metering specialist (not just an installer I started out as an apprentice cable jointer for a DNO). A three phase supply for a domestic property 3-6 bedroom with 2 EV's and a heat pump is overkill.

Single phase supply is rated at 100-120amps most DNO's will say 80-100amps at the supply head because 99% of network infrastructure is nearly 70years old and only 10mm² cable and Ohms law says that's all you can get!

If your property is fed from a 3 phase cable you are the lucky one! Very few are depending on the age of the property and age of the supply. Usually a 3 phase cable is split at a major road junction so each street gets one phase at a time or a group of houses get fed from the same phase. Making phase isolation easy.

To utilise the three phase supply the way you want will cost you two lots of standing charge as you would require two meters but no additional work would be needed to your existing installation other than adding the phases and having the extra meter installed for the garage supply. To make use of three phase for load balancing and stability (what its intended for) you would need a three phase meter and consumer unit installed and a while lot of new wiring to the consumer unit. That said you could have a secondary CCu installed (3phase) and then feed one phase from that to thee existing CCu.

Biggest question is are you intending to stay in the property long term for the changes to be worth while?
 

BigBoy

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Graetzbridge said:
He is asking if he needs to do anything with the existing consumer unit. I'm pretty sure the Electricity Authority won't allow it in a domestic residence. Apart from anything else his proposed 3-phase supply would be 400 V line to line.
Click to expand...
Nothing wrong with three phase on domestic settings, it's quite common for larger properties.
 

Graetzbridge

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BigBoy said:
Nothing wrong with three phase on domestic settings, it's quite common for larger properties.
Click to expand...
Mike was asking if he needs to do anything with the existing consumer unit like balance it across three phases. The existing unit won't do that. It would need a completely new supply.
And I think you are incorrect - three-phase on domestic supplies is not very common.
 
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