Ampage for EV charger?
Discussion
Please be kind as I'm new to this sort of thing... I'm buying a new house and they've asked what sort of power requirements I have for the external garage as they're going to lay the cable.
Now to my (largely empty in this matter) mind what they want to know is the Amp requirements so they can work out what diameter cable they need.
I don't have an electric car, but it makes sense to my mind to future proof the garage. After some googling it appears most of the home chargers are rated for 16 or 32 amps?
So 32A is required for the charger right? (I'll then work out what else I need for lights, compressor, other tools etc.)
Now to my (largely empty in this matter) mind what they want to know is the Amp requirements so they can work out what diameter cable they need.
I don't have an electric car, but it makes sense to my mind to future proof the garage. After some googling it appears most of the home chargers are rated for 16 or 32 amps?
So 32A is required for the charger right? (I'll then work out what else I need for lights, compressor, other tools etc.)
Yeah you see that's me getting confused already... For a free phase charger presumably I'd need a three phase consumer unit or something in the house?
I had planned on just using whatever consumer unit in the house they included in the build, then have them run a big ass cable to a secondary consumer unit in the garage. Then run the charger from there.
Is that inadequate future proofing then?
I had planned on just using whatever consumer unit in the house they included in the build, then have them run a big ass cable to a secondary consumer unit in the garage. Then run the charger from there.
Is that inadequate future proofing then?
32A (7kW) single phase is most common now, both for what people fit to their houses, and what cars will accept.
My plan for my garage (which will likely be occasional charging, I have a charger on the driveway) is to do at least one 32A commando socket for powering welder, beefy compressor, etc. Then if you do need to charge a car, something like this will do the job nicely: https://evonestop.co.uk/products/ev-charging-cable...
My plan for my garage (which will likely be occasional charging, I have a charger on the driveway) is to do at least one 32A commando socket for powering welder, beefy compressor, etc. Then if you do need to charge a car, something like this will do the job nicely: https://evonestop.co.uk/products/ev-charging-cable...
Scrump said:
If you can’t get 3 phase then 32 amp.
My charger is 16amp but all the cabling etc is 32amp as the cost difference at the time of installation is minimal.
If I did it again I would get cabling for two 32amp points installed so I could have two chargers.
If I understand correctly, if I did that I'd need a rating of something like 70A cable run from the consumer unit in the house to the garage... So about 10mm^3 and £403 + VAT per hundred meters... Excluding significant delivery costs.My charger is 16amp but all the cabling etc is 32amp as the cost difference at the time of installation is minimal.
If I did it again I would get cabling for two 32amp points installed so I could have two chargers.
Not impossible I guess, but getting pricey for sure!
Scrump said:
If you just run 32 amp cable out to the garage then you would not be able to have any other electrical draw whilst charging a car with a 32 amp charger, or am I missing something?
Possibly.So the the 10mm^3 cable I found was rated to 70A, so that would be 32A chargers x 2 + 6A for other appliances.
Depending on the temperature, and, presumably, the length of the cable.
So I would probably need something with a higher rating in reality.
I think I may just scrap this idea. It'd cost me a bloody fortune for a car I don't even own yet!
6mm^2 cable will satisfy the charge demand of 7kW. Installers are fitting plenty every day. I don’t think a fridge would worry me but thinks like pressure washers or mowers just don’t use at same time or get a charge that power balance, either the Zappi or Wallbox Pulsar with the power boost device.
With a new build then a 10mm^2 cable to a separate garage consumer would be tempting.
With a new build then a 10mm^2 cable to a separate garage consumer would be tempting.
Edited by JonnyVTEC on Thursday 4th March 12:13
Dont scrimp....
If there is nothing there then best get a decent run to your garage. Id be looking at a seperate consumer unit in the garage and some spare capacity - you mentioned providing for two chargers ?
Saves the need for an upgrade later, and gives you capacity for any equipment being put in your garage.
Dont run your garage through your consumer unit as that takes capacity away from your consumer.
incoming supply 100A run through service head to meter to a 100A isolator.
25mm Cables from isolator to Henley blocks one for Live and one for Neutral. 25mm tails from Henley blocks to local consumenr unit.
You need to run from the henley blocks to the garage, this is where you need to decide on what you want at the garage, do you take the full 100 A out ? 25mm cable out to the garage, or fit a 40A double pole breaker and run out a 16mm cable to the garage consumer unit. earth cables would be run to a 100A earth terminal block. utility earth, earth to local consumer unit, and a point to connect the earth cable going to the garage consumer. cable sized according to the regs. and the demand.
splitting the consumer reduces the load on the local consumenr unit and it also allows the RCD to be protecting the board. If you connected the garage to the main db then your main db rcd would operate on a fault at the garage consumner board.
Earth would need to
If there is nothing there then best get a decent run to your garage. Id be looking at a seperate consumer unit in the garage and some spare capacity - you mentioned providing for two chargers ?
Saves the need for an upgrade later, and gives you capacity for any equipment being put in your garage.
Dont run your garage through your consumer unit as that takes capacity away from your consumer.
incoming supply 100A run through service head to meter to a 100A isolator.
25mm Cables from isolator to Henley blocks one for Live and one for Neutral. 25mm tails from Henley blocks to local consumenr unit.
You need to run from the henley blocks to the garage, this is where you need to decide on what you want at the garage, do you take the full 100 A out ? 25mm cable out to the garage, or fit a 40A double pole breaker and run out a 16mm cable to the garage consumer unit. earth cables would be run to a 100A earth terminal block. utility earth, earth to local consumer unit, and a point to connect the earth cable going to the garage consumer. cable sized according to the regs. and the demand.
splitting the consumer reduces the load on the local consumenr unit and it also allows the RCD to be protecting the board. If you connected the garage to the main db then your main db rcd would operate on a fault at the garage consumner board.
Earth would need to
ruggedscotty said:
Dont scrimp....
If there is nothing there then best get a decent run to your garage. Id be looking at a seperate consumer unit in the garage and some spare capacity - you mentioned providing for two chargers ?
Saves the need for an upgrade later, and gives you capacity for any equipment being put in your garage.
Dont run your garage through your consumer unit as that takes capacity away from your consumer.
incoming supply 100A run through service head to meter to a 100A isolator.
25mm Cables from isolator to Henley blocks one for Live and one for Neutral. 25mm tails from Henley blocks to local consumenr unit.
You need to run from the henley blocks to the garage, this is where you need to decide on what you want at the garage, do you take the full 100 A out ? 25mm cable out to the garage, or fit a 40A double pole breaker and run out a 16mm cable to the garage consumer unit. earth cables would be run to a 100A earth terminal block. utility earth, earth to local consumer unit, and a point to connect the earth cable going to the garage consumer. cable sized according to the regs. and the demand.
splitting the consumer reduces the load on the local consumenr unit and it also allows the RCD to be protecting the board. If you connected the garage to the main db then your main db rcd would operate on a fault at the garage consumner board.
Earth would need to
I would say as above. The only thing I would add is maybe use a duct rather than bury the cable directly. One day, when your requirements change, it will be easy to upgrade. On cost of a bit of ducting won't be much... alternatively go the whole hog now and put in a three phase 25mm sub-main. I realise that you only presently have 1-ph incomming, but who knows if that might need upgrading in the future.If there is nothing there then best get a decent run to your garage. Id be looking at a seperate consumer unit in the garage and some spare capacity - you mentioned providing for two chargers ?
Saves the need for an upgrade later, and gives you capacity for any equipment being put in your garage.
Dont run your garage through your consumer unit as that takes capacity away from your consumer.
incoming supply 100A run through service head to meter to a 100A isolator.
25mm Cables from isolator to Henley blocks one for Live and one for Neutral. 25mm tails from Henley blocks to local consumenr unit.
You need to run from the henley blocks to the garage, this is where you need to decide on what you want at the garage, do you take the full 100 A out ? 25mm cable out to the garage, or fit a 40A double pole breaker and run out a 16mm cable to the garage consumer unit. earth cables would be run to a 100A earth terminal block. utility earth, earth to local consumer unit, and a point to connect the earth cable going to the garage consumer. cable sized according to the regs. and the demand.
splitting the consumer reduces the load on the local consumenr unit and it also allows the RCD to be protecting the board. If you connected the garage to the main db then your main db rcd would operate on a fault at the garage consumner board.
Earth would need to
I am informed that our local DNO is now only installing 3-ph for new supplies - typically only one is used at the consumer unit, but the 3-ph is brought to the cutout ready.
The only problem with all of this, is it all gets a bit silly and your wall starts to look like a plant room. I guess in a new build it will be really difficult to install a new CU neatly. I don't like the idea of putting non-DNO kit in the meter cupboard.
DNO come to check my charge install after (I heard they see alot where the charger is spurred off BEFORE the meter!)
I asked about the content in mine as has Henly block and additional fuse box
'No issues mate, that box is yours and any problems with having to move stuff will be yours anyway'
I asked about the content in mine as has Henly block and additional fuse box
'No issues mate, that box is yours and any problems with having to move stuff will be yours anyway'
No ideas for a name said:
ruggedscotty said:
Dont scrimp....
If there is nothing there then best get a decent run to your garage. Id be looking at a seperate consumer unit in the garage and some spare capacity - you mentioned providing for two chargers ?
Saves the need for an upgrade later, and gives you capacity for any equipment being put in your garage.
Dont run your garage through your consumer unit as that takes capacity away from your consumer.
incoming supply 100A run through service head to meter to a 100A isolator.
25mm Cables from isolator to Henley blocks one for Live and one for Neutral. 25mm tails from Henley blocks to local consumenr unit.
You need to run from the henley blocks to the garage, this is where you need to decide on what you want at the garage, do you take the full 100 A out ? 25mm cable out to the garage, or fit a 40A double pole breaker and run out a 16mm cable to the garage consumer unit. earth cables would be run to a 100A earth terminal block. utility earth, earth to local consumer unit, and a point to connect the earth cable going to the garage consumer. cable sized according to the regs. and the demand.
splitting the consumer reduces the load on the local consumenr unit and it also allows the RCD to be protecting the board. If you connected the garage to the main db then your main db rcd would operate on a fault at the garage consumner board.
Earth would need to
I would say as above. The only thing I would add is maybe use a duct rather than bury the cable directly. One day, when your requirements change, it will be easy to upgrade. On cost of a bit of ducting won't be much... alternatively go the whole hog now and put in a three phase 25mm sub-main. I realise that you only presently have 1-ph incomming, but who knows if that might need upgrading in the future.If there is nothing there then best get a decent run to your garage. Id be looking at a seperate consumer unit in the garage and some spare capacity - you mentioned providing for two chargers ?
Saves the need for an upgrade later, and gives you capacity for any equipment being put in your garage.
Dont run your garage through your consumer unit as that takes capacity away from your consumer.
incoming supply 100A run through service head to meter to a 100A isolator.
25mm Cables from isolator to Henley blocks one for Live and one for Neutral. 25mm tails from Henley blocks to local consumenr unit.
You need to run from the henley blocks to the garage, this is where you need to decide on what you want at the garage, do you take the full 100 A out ? 25mm cable out to the garage, or fit a 40A double pole breaker and run out a 16mm cable to the garage consumer unit. earth cables would be run to a 100A earth terminal block. utility earth, earth to local consumer unit, and a point to connect the earth cable going to the garage consumer. cable sized according to the regs. and the demand.
splitting the consumer reduces the load on the local consumenr unit and it also allows the RCD to be protecting the board. If you connected the garage to the main db then your main db rcd would operate on a fault at the garage consumner board.
Earth would need to
I am informed that our local DNO is now only installing 3-ph for new supplies - typically only one is used at the consumer unit, but the 3-ph is brought to the cutout ready.
The only problem with all of this, is it all gets a bit silly and your wall starts to look like a plant room. I guess in a new build it will be really difficult to install a new CU neatly. I don't like the idea of putting non-DNO kit in the meter cupboard.
I've contacted the builder and asked if (a) it's three phase supply or if this is possible (b) if they can run a seperate consumer unit to the garage (so not to draw from the 100A main supply) (c) if those options aren't viable due my finances, I'll check Amp requirements with expert, then ask that they run a 10mm^3(?) to a separate consumer unit, I'll see if they can use ducting.
I'm curious how flexible they're willing to be during the build process, if they can't be bothered however I suspect they'll just quote silly money for the changes, and I'll be left firmly with option (c).
It would be great "not to skimp", but this is my first big house, and doing the floors, turfing the lawn, decorating, buying furniture, building fences, building storage in the loft, and then adding a side door the garage, as well as kitting it out, all are fighting for my finances in the here and now, rather than "one day when I eventually have the funds spare to buy an electric car".
You can insist on a 3phase install, it's nothing to do with the builders it's your local power grid which will be putting that in. You might have to make some phone calls and fire off a few emails but you will be able to get it. It is usually only a little more expensive, I think mine was £900.
You can just use normal consumer units with 3 phase, you could have 1 in the garage and 1 in the house.
You'll be able to do whatever you want re chargers then.
Also: You may be told 3phase will be crazy expensive, will be £10k, etc. etc. so was I but do not listen to any of this until someone from the actual grid install team has a look. This is your one chance to put this in at the cheapest possible quote.
You can just use normal consumer units with 3 phase, you could have 1 in the garage and 1 in the house.
You'll be able to do whatever you want re chargers then.
Also: You may be told 3phase will be crazy expensive, will be £10k, etc. etc. so was I but do not listen to any of this until someone from the actual grid install team has a look. This is your one chance to put this in at the cheapest possible quote.
Edited by jjwilde on Thursday 4th March 11:19
It sounds like you've some good advice with regard to the car charger...
Also, have a think about solar and batteries. Quite often these end up in the garage (because people don't want them in the house), and so you may want that big 70A or more cable so you can power the house from the garage batteries etc.
Also, have a think about solar and batteries. Quite often these end up in the garage (because people don't want them in the house), and so you may want that big 70A or more cable so you can power the house from the garage batteries etc.
jjwilde said:
You can insist on a 3phase install, it's nothing to do with the builders it's your local power grid which will be putting that in. You might have to make some phone calls and fire off a few emails but you will be able to get it. It is usually only a little more expensive, I think mine was £900.
You can just use normal consumer units with 3 phase, you could have 1 in the garage and 1 in the house.
You'll be able to do whatever you want re chargers then.
Also: You may be told 3phase will be crazy expensive, will be £10k, etc. etc. so was I but do not listen to any of this until someone from the actual grid install team has a look. This is your one chance to put this in at the cheapest possible quote.
Quick question about this as I'm ignorant of how this three phase thing works...You can just use normal consumer units with 3 phase, you could have 1 in the garage and 1 in the house.
You'll be able to do whatever you want re chargers then.
Also: You may be told 3phase will be crazy expensive, will be £10k, etc. etc. so was I but do not listen to any of this until someone from the actual grid install team has a look. This is your one chance to put this in at the cheapest possible quote.
Edited by jjwilde on Thursday 4th March 11:19
So if I insist on a three phase for the house, presumably I don't need a seperate "isolated 100A" supply or anything?
If I get three phase, is the total draw for the house a potential 300A so I can just run a big ass cable from the consumer unit in the house to a secondary consumer unit in the garage?
jjwilde said:
You can insist on a 3phase install, it's nothing to do with the builders it's your local power grid which will be putting that in. You might have to make some phone calls and fire off a few emails but you will be able to get it. It is usually only a little more expensive, I think mine was £900.
You can just use normal consumer units with 3 phase, you could have 1 in the garage and 1 in the house.
You'll be able to do whatever you want re chargers then.
Also: You may be told 3phase will be crazy expensive, will be £10k, etc. etc. so was I but do not listen to any of this until someone from the actual grid install team has a look. This is your one chance to put this in at the cheapest possible quote.
You can insist on three phase but developers often ask extortionate prices to fit it in order to discourage deviation from their standard offering. No harm in asking though.You can just use normal consumer units with 3 phase, you could have 1 in the garage and 1 in the house.
You'll be able to do whatever you want re chargers then.
Also: You may be told 3phase will be crazy expensive, will be £10k, etc. etc. so was I but do not listen to any of this until someone from the actual grid install team has a look. This is your one chance to put this in at the cheapest possible quote.
Edited by jjwilde on Thursday 4th March 11:19
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