Speak EV - Electric Car Forums banner

1 - 20 of 34 Posts

·
Registered
Joined
·
47 Posts
Discussion Starter #1
Hi
We are currently renovating a house for us to live in. It will be back to brick, new wiring, new water supply, new pipes etc. Also looking to get as much solar as possible. I think we have the chance of getting about 6kwh. We currently have a phev but will have an EV when we move in.

Anyhow I am wondering what is the benefits and negatives of getting a new 3 phase electricity supply fitted.
 

·
Registered
Joined
·
2,249 Posts
Contact your DNO, they should be able to give you options as to your choice of qualified contractor, or the DNO themselves, depending on your scope. Is is a suburban, urban or rural setting?
 

·
Registered
Joined
·
2,249 Posts
Positives will be the size of PV, windpowrer, EVSE you can connect. You can run three phase motors in your workshop. None of these may have any actual value to you depending on your circumstances and the size of your plot.
 

·
Registered
Joined
·
47 Posts
Discussion Starter #5
Contact your DNO, they should be able to give you options as to your choice of qualified contractor, or the DNO themselves, depending on your scope. Is is a suburban, urban or rural setting?
We are in an urban area, 1-2 miles from Sheffield city centre.
PS what does DNO stand for?
 

·
Registered
Joined
·
47 Posts
Discussion Starter #6
Positives will be the size of PV, windpowrer, EVSE you can connect. You can run three phase motors in your workshop. None of these may have any actual value to you depending on your circumstances and the size of your plot.
We are urban so no windmills I'm afraid. There will be a garage which will be a mini workshop but only really for wood work. Energy wise there will be a steam room that might consume a lot of electricity when it is turned on, aside from that it is just normal household appliances.
 

·
Registered
Joined
·
2,249 Posts
From what you describe, a single phase 100A should be suitable, maybe a bit of load control if you fit electric shower(s). The DNO is the company the runs the electricity wires and transformers downstream from the main grid (Distribution Network Operator). They have a fixed geographical monopoly.
 

·
Registered
Joined
·
2,249 Posts
By definition, your DNO will not be your electricity supplier or meter provider. These are all separated services even if you have a supply from one of the companies that bears a similar name.
 

·
Registered
Joined
·
2,249 Posts
Three phase is good for woodworking machines. That would be a big plus for me
Three phase is good for all machines but for little ones and woodworking there are lots of workarounds. Speed control is pretty easy with single phase. I guess if you are turning up whole tree trunks or running a sawmill, 3 phase would be mandatory🤗Mini workshop sounds more like light joinery work, bench router/planer sort of stuff using DIY machines????? OP mentioned that steam room might be heavy user
 

·
Registered
Joined
·
1,886 Posts
We have a 3 phase supply. On the plus side, we were able to fit a 9kW PV system without having to negotiate with the DNO, since export is less than 15A (or is it 16A?) per phase.
And I'll be able to fit an 11kW charger for a Tesla Model 3.
On the downside, we have had issues getting replacement meters as they mostly don't seem to cater to 3 phase supplies for smart meters, and we have had occasional issues switching suppliers (but that was likely down to the three rate supply we had - Day, Night and Heat).
If it won't cost you much, it might be worth it, but a 100A single phase supply should be adequate for most purposes.

If you're completely refitting a building, I trust you'll be using a heat pump system? If you can install underfloor heating, a "water based" heat pump may be a good idea. If not, I'd recommend looking closely at Air-to-Air Heat pumps for space heating.
 

·
Registered
Joined
·
1,905 Posts
If you are having a new supply cable installed, it is probably worth going for 3-phase as the big expense is digging the trench to the DNO's cable in the street. If you can cope with the capacity of your existing supply cable by using load management systems (eg, turning down the charging rate on your car while you are using the steam room) I would stay with the existing cable.

For guidance, with load control a 60A supply can supply 100kWh in the 7-hour Economy 7 cheap rate period, and for a 100A supply (which I understand some DNO's do not like to be run continuously at more than 80A on a warm day) your supply should be good for about 130kWh per night.

How many miles do you travel in a day (and more to the point, how many miles are you likely to travel on the day after returning from a long journey with a flat traction battery)? A good winter allowance is 1 kWh for every three miles (subject to the size of your vehicle battery).

As with @jmacneil I have not yet got a smart meter installed as Utility Warehouse say there are none available for 3-phase supplies (we have a 3-phase supply because of a large winter off-peak heating load).
 

·
Registered
Joined
·
1,886 Posts
As with @jmacneil I have not yet got a smart meter installed as Utility Warehouse say there are none available for 3-phase supplies (we have a 3-phase supply because of a large winter off-peak heating load).
Yeah, when we moved in our house had five storage heaters and our "cold winter's day" power usage was typically 135kWh or so.
 

·
Registered
Joined
·
2,249 Posts
Is that rather large 136kWh number reduced by 3 with heat pumps, or has your insulation made an even bigger difference ( or have you just hardened up):oops:
 

·
Registered
Joined
·
28 Posts
Hi
We are currently renovating a house for us to live in. It will be back to brick, new wiring, new water supply, new pipes etc. Also looking to get as much solar as possible. I think we have the chance of getting about 6kwh. We currently have a phev but will have an EV when we move in.

Anyhow I am wondering what is the benefits and negatives of getting a new 3 phase electricity supply fitted.

If you have 3 phase coming in, go for it.

I have 3 phase, but only use one of them for the time being.

The potential unknown cost of going to a 3 phase from the house electrics put me off a little after speaking to a few people about it, but if you're starting from scratch then go for it. I will convert in the not too distant future, for the time being i've got a 7kw which is alright, but id rather have 22.

A 22kw charger would be awesome at home.
 

·
Registered
Joined
·
2,249 Posts
Whoa enthusiasts.

Keep in mind 3 phase is NOT standard for UK domestic so you will encounter some additional costs even once you have DNO bit done (metering, wiring, switchgear etc) If it's just an ordinary urban house and a large rural property/mansion, I seriously doubt there is any real justification.
 

·
Registered
Joined
·
3,014 Posts
You can get single phase to 3 phase converters for running modest-power machinery, I have one driving my Coolchester Chipmaster lathe. It runs off a conventional 13A socket no sweat, probably 2 hp or thereabouts. The fantastic advantage of this over conventional 3-phase is that I can twiddle the frequency from 50 Hz right down to 0 Hz! On my lathe this means I can rotate the workpiece microscopically slowly, and stop it precisely. I used that to cut a thread where I had to take multiple passes on the end of a shaft where I couldn't have a clearance groove to run into. I didn't have a fancy Coventry die-chuck to do the job in one pass, but this simulated that perfectly. And the ability to reverse the motor, again from the same small control panel, makes it easy to back-out the cutter without having to worry about engaging the feed-thread correctly.
 

·
Registered
Joined
·
1,886 Posts
Is that rather large 136kWh number reduced by 3 with heat pumps, or has your insulation made an even bigger difference ( or have you just hardened up):oops:
To be fair, I haven't measured single day power consumption recently, but annual consumption from the grid had gone down from about 27000kWh to about 9500kWh or so. That was before installing better controls on the heat pumps - so they basically just ran almost continuously controlled by the thermostat (except for warmer days in summer). I now have WiFi enabled controllers connected to them all, so expect slightly lower usage during winter. We have also added an EV in the meantime, which will add a few thousand kWh to the total (mostly on cheap rate overnight).

One advantage of knowing the ~135kWh figure was that I was fairly confident that we didn't need much more than 5kW of continuous heat input even in pretty cold weather - which can easily be supplied by the heat pumps.

We're hoping to soon install a Sunamp phase change thermal store along with an 'Eddi' controller to monitor all three phases so that we can make better use of our PV production (and get mains pressure hot water, yay!) - at the moment we have an old fashioned hot water tank, with the immerser controlled by a 'Solar iBoost' which can only monitor one phase, so we don't make the best use of our PV generation to provide hot water - you could consider that another potential downside os a three phase supply: it's harder to use devices such as smart meters and solar diverters because they're almost all designed for single phase.
 
1 - 20 of 34 Posts
Top