Upgrading house to 3 phase supply

Soldato
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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.

Domestic three phase is very common on large properties (I make a living from it!)

Very true existing will not as per my original post, a load balancer would be required.
 
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Domestic three phase is very common on large properties (I make a living from it!)

Very true existing will not as per my original post, a load balancer would be required.
Not not at all common on domestic supplies.
But I have known a few three phase systems in London. My company lighting dimmers for them. But most of our projects were commercial buildings. Some of them quite large like the Burj al Arab. I got involved with these projects to sort out harmonics problems.

My own field, including harmonics, was large industrial variable speed drives. Different scale.
 
Soldato
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@Graetzbridge must just be this area then. I work in metering and 3 phase is common in the large 5 story properties here.

As I said earlier I work for a supplier and trained as a cable jointer 25 years ago. Three phase domestic supply in the southwest is more common than you would expect.
 
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Associate
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Well at least I’ve prompted some varied discussion here!

Agreed, it isn’t a common thing, but definitely not unheard of, from my own research there’s plenty of sites who are recommending going down this route if costs & logistics support it therefore I’m guessing it will be common in the future as EVs and alternative fuel sources become prevalent.

I don’t even have an EV now, just thinking ahead and not wanting to rip up an expensive driveway in 10 years.

Given this, I’ve had another idea too that I’ll discuss with the DNO unless it’s a witchcraft. What about just running the cable in in readiness for future connection at a later date. Just leave it unterminated at both ends for the time being?

I’ll update the thread with any meaningful progress.
 
Soldato
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Based on current tech and 1x vehicle? Yes.

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

It may change in the future but most EVs can't even utilise 22kW AC. Off the top of my head the Model 3's current limit is 11kW and the Leaf is 6kW. So three-phase will make little difference to individual charge speeds, but it would help with charging multiple EVs simultaneously, but you could still charge 3 EVs from empty to full overnight (12 hours or so) on single-phase so meh.

It's the difference between AC/DC (if you had the 250kW etc speeds as charging capabilities in your head).
 
Soldato
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Given this, I’ve had another idea too that I’ll discuss with the DNO unless it’s a witchcraft. What about just running the cable in in readiness for future connection at a later date. Just leave it unterminated at both ends for the time being?

You don't want to be leaving big chunks of cable in the ground un used, water ingress to the cable would kill off any potential usefulness in the future.

You can have the head upgraded but most suppliers will charge you for it and unless you can put a good case forwards for it being upgraded they will not do it even if you did pay.
 
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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

Theoretically no you could leave the mains board as is and use one of the single-phase supplies. Then you would have to fit a 3Phase Isolator fused to the correct ampage you require
 
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Theoretically no you could leave the mains board as is and use one of the single-phase supplies. Then you would have to fit a 3Phase Isolator fused to the correct ampage you require
Not a particularly cost effective way to perform an upgrade more of a side grade with two wasted phases, especially as you will be metered and standing charge will be base on three phase supply.

100a incoming main is more than enough to run a fully electric household with 2 EV's and heapump. Especially if you operate them at the set cheaper tariff times i.e in the night time hours. When you are not doing anything else!

What's your curent standing charge? Three phase standing charge being 3-6x more expensive and then work out if it's worth it (average UK standing charge is £89 per year).
 
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going back a few years been in this house 35 but about 15 years ago enquired about ruuning 3 phase as i had a large compressor (3 phase) i live on a main road and even then the cost from electricity provider was around 15 grand. then the council had to be informed as in there words if i wanted three phase i might be looking at possible business use, tbh when i heard the figure i switched off and bought a convertor ran the compressor happily and now also runs my 2 poster:)

strange thing was about the same time father in law had a new house built and the board put three phase in as standard grrrr.
 

Jez

Jez

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100a incoming main is more than enough to run a fully electric household with 2 EV's and heapump. Especially if you operate them at the set cheaper tariff times i.e in the night time hours. When you are not doing anything else!

Really not convinced that it is? I have 63A worth of heating, a 13A immersion heater, a range cooker rated at >60A. I appreciate diversity should obviously be taken into account but it seems too close to the bone to me? Our new property is very similar - the heating in that is (going to be) Air Source, so more efficient, but still >50A at full load as it is a much larger area, plus water heating, dryer, washing machines, ovens/hobs etc.

I have never had an actual issue, granted, but it does worry me a little in cold weather when the heating is fully firing and then my wife also turns on dryers and ovens etc. EVs on paper don't work on a 100A supply with electric heat as far as i can tell you'd have to be mega careful with timing?

(Not a qualified electrician, but i did the whole installation here and am doing in our new property, uni was electrical & electronic engineering).
 
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Good chargers have a CT to monitor grid load and will ramp down the charge current if you're getting close to the maximum, plus you'll probably be charging overnight during cheap electricity when the heating is probably turned down and you won't be cooking or doing laundry?
 

Jez

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Good chargers have a CT to monitor grid load and will ramp down the charge current if you're getting close to the maximum, plus you'll probably be charging overnight during cheap electricity when the heating is probably turned down and you won't be cooking or doing laundry?
Hey Olly :) I have never really looked into EV chargers beyond basic commando 16a plug in ones out of interest (I only have diesel cars but this can only last so long!).

I wasn’t aware at all that any of the better chargers monitored your overall grid load. I knew they featured timers and smart features but not that. That really is good and does turn this into a non issue. In that case yep, sorry to BigBoy for questioning it, even for a large electric household then 3ph seems to not really be required. We’ll never run more peak load than we do currently and it’s never tripped yet!
 
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Really not convinced that it is? I have 63A worth of heating, a 13A immersion heater, a range cooker rated at >60A. I appreciate diversity should obviously be taken into account but it seems too close to the bone to me? Our new property is very similar - the heating in that is (going to be) Air Source, so more efficient, but still >50A at full load as it is a much larger area, plus water heating, dryer, washing machines, ovens/hobs etc.

I have never had an actual issue, granted, but it does worry me a little in cold weather when the heating is fully firing and then my wife also turns on dryers and ovens etc. EVs on paper don't work on a 100A supply with electric heat as far as i can tell you'd have to be mega careful with timing?

(Not a qualified electrician, but i did the whole installation here and am doing in our new property, uni was electrical & electronic engineering).
Is that really what electric cookers are:eek:. I wouldn't have thought your immersion was on all the time (unless you're that person with 16000kwh yearly useage:D). I get your point though.
 

Jez

Jez

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Is that really what electric cookers are:eek:. I wouldn't have thought your immersion was on all the time (unless you're that person with 16000kwh yearly useage:D). I get your point though.
Rating doesn’t mean it is using anything like that amount, the cooker is “rated” at something like 65A (6 hobs 3 ovens, plate warmer and grill). In reality you never run all of the elements at the same time but overall the picture is that in theory, just at the wrong time, we are way way over 100a. As I say, never actually been a problem, we’ve never tripped the 100a main breaker. My thought was that a couple of EVs would be the straw that broke the camels back :) Not an issue with grid monitoring as mentioned by Olly though.

Immersion won’t run much but is unpredictable, the tank it heats is an extremely well insulated megaflo , barely warm to the touch despite very hot water.
 
Soldato
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correct me if I'm wrong but balancing the load is only needed on high usage (commercial) customers when they're billed on peak usage (half hourly?) when the cost is based on peak usage on any of the three phases measured every half hour, so spreading it out over the three would reduce peak usage/cost... rather than the usual total kWh that single phase/domestic customers would be billed on

fairly sure lower use/domestic customers on three phase still only get billed for the total kWh used across all three phases so assuming the unit price is still the same the only difference would be the standing charge
 
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Not a particularly cost effective way to perform an upgrade more of a side grade with two wasted phases, especially as you will be metered and standing charge will be base on three phase supply.

100a incoming main is more than enough to run a fully electric household with 2 EV's and heapump. Especially if you operate them at the set cheaper tariff times i.e in the night time hours. When you are not doing anything else!

What's your curent standing charge? Three phase standing charge being 3-6x more expensive and then work out if it's worth it (average UK standing charge is £89 per year).

Unless you want a big charger 22Kw Then you are going to need 3Phase
 
Soldato
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Unless you want a big charger 22Kw Then you are going to need 3Phase
Installing a rapid charge will completely negate the possibility of an off peak tariff, you cannot get an off peak three phase tariff. Most cars will charge in less than three hours on a 13a plug charger so to install a rapid charge at home is pointless!

Quoting max input figures is pointless as that is not current draw. ASHP at 50a for example is it running at full tilt, they are designed not to work that way so again pointless quoting input figures.
 
Soldato
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Really not convinced that it is? I have 63A worth of heating, a 13A immersion heater, a range cooker rated at >60A. I appreciate diversity should obviously be taken into account but it seems too close to the bone to me? Our new property is very similar - the heating in that is (going to be) Air Source, so more efficient, but still >50A at full load as it is a much larger area, plus water heating, dryer, washing machines, ovens/hobs etc.

I have never had an actual issue, granted, but it does worry me a little in cold weather when the heating is fully firing and then my wife also turns on dryers and ovens etc. EVs on paper don't work on a 100A supply with electric heat as far as i can tell you'd have to be mega careful with timing?

(Not a qualified electrician, but i did the whole installation here and am doing in our new property, uni was electrical & electronic engineering).
Quoting max rated input values is not the way to go about it, see my above post.
 
Soldato
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correct me if I'm wrong but balancing the load is only needed on high usage (commercial) customers when they're billed on peak usage (half hourly?) when the cost is based on peak usage on any of the three phases measured every half hour, so spreading it out over the three would reduce peak usage/cost... rather than the usual total kWh that single phase/domestic customers would be billed on

fairly sure lower use/domestic customers on three phase still only get billed for the total kWh used across all three phases so assuming the unit price is still the same the only difference would be the standing charge

Unit price and standing charge are higher for three phase around 3-6x higher.
 
Soldato
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3-6x for both unit price and standing charge?!

maybe different for region? we always had three phases (100A) coming in to the property but on a single phase meter...had the need to get three phase for some machinery so all that needed to be done was getting a three phase meter installed, I'd have to look but the price increase was more like 10-20% for unit price?


e : maybe even the same unit price, bad memory...
 
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