Pre-wiring for an electric car charger, any tips?

[Boss13]

Renovating our house at the moment. Have the opportunity to put wiring in place for a car charger which will undoubtedly be required at some point in the future.

Any tips on what should be done, i.e. which wire, which fuse, etc.? Tempted to just ask a company to come in and install a charger, but I don't have an electric car at the moment and may be a couple of years before I go for one, so if I can successfully pre-wire to the place I feel it would go that may be a good interim solution. Appreciate any thoughts from those who may have been through similar.

[AndyMilts]

If you have an electric car you get a government grant to help with the costs of installation of a charger.

There are a few options for chargers and the 7kw option is where I would go. You can get 11or 22kw faster but needs 3 phase and also the extra speed for me makes little difference as I charge over night. As long as the car is charged for the next day that’s all I cared about if it took 5 or 9 hours did not really matter.

This might help

https://www.autocar.co.uk/car-news/a...ctric-car-home

[Dave+63]

Home chargers are either 16 or 32amp. Most cars charge at 32amps these days so your cable needs to be able to take that current continuously.

I think I have a 40amp trip in the garage consumer unit but I’ll check next time I’m up there and confirm.

[thieuster]

Put solar panels on your roof as well.

(With Dutch prices in mind), you'll pay and arm and a leg (more) when you hook an electric car on the charger at home.

[Dave+63]

Put solar panels on your roof as well.

(With Dutch prices in mind), you'll pay and arm and a leg (more) when you hook an electric car on the charger at home.

It’s really cheap if you charge off peak on the cheap rate tariffs over here Menno.

[thieuster]

I guy I know owns a type X. It consultant with large hospitals has his customers. The battery of his X needs a full recharge every day (long distance between his house and work). His home's electricity bill has more than doubled: 220 euros to 495 euros/month. His wife (a chartered accountant) nearly got the proverbial stroke when she noticed what had happened. She was not keen on the big bulky car in the first place. Fuel prices are over 9 euro/gallon here, so slowly she starts to come around, knowing that it would cost a king's randsom to fill a fuel tank for the same trip.

[Boss13]

If you have an electric car you get a government grant to help with the costs of installation of a charger.

There are a few options for chargers and the 7kw option is where I would go. You can get 11or 22kw faster but needs 3 phase and also the extra speed for me makes little difference as I charge over night. As long as the car is charged for the next day that’s all I cared about if it took 5 or 9 hours did not really matter.

This might help

https://www.autocar.co.uk/car-news/a...ctric-car-home

Thanks all

I guess the issue I have is that I don’t have an electric car and so no grant.

Willing to pay for it. Just need to understand how the wiring works. I guess this is more an electrician question than an electric car owner question.

Thanks Dave for your comments. I did also read a 32a fuse may be required. Just not sure on the cable required.

[Boss13]

Duplicate.

[CriticalMass]

I’m sure other manufacturers do something similar but my Zappi charger is very good at managing the charging process as economically as possible- in particular integrating power from my solar panels.

I’m not sure how much benefit there is for the government grant. You have to use an approved installer and I suspect the grant just increases their profit margin…

[Pennywise]

I’d be putting this in, dependant on run length and load. The cable has an integrated cat 5 within it for the smart metering communication part of the charger.

https://www.toolstation.com/cut-to-l...r-cable/p82520


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[stuie-t]

When we had our charger installed a couple of years ago we also had to have the main fuse upgraded. We went from 60 to 80 amp as that was a straight swap and therefore free but if you are planning ahead then get a 100 amp fuse so that you can run the charger along with an induction cooker and other energy intensive household appliances for example. Will also likely need the meter tails upgraded.


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[Dave+63]

Here’s mine, 32amp Mcb and armoured cable. I’m not sure whether the cable is 32 or 40 amp rating.


All professionally installed by approved fitter way back when.

[adrianw]

Here’s mine, 32amp Mcb and armoured cable. I’m not sure whether the cable is 32 or 40 amp rating.


All professionally installed by approved fitter way back when.

Should be RCBO not NCB, also if it has been worked on it should have been changed to a metal box

[Dave+63]

Should be RCBO not NCB, also if it has been worked on it should have been changed to a metal box

It was installed in 2015 by an approved charger fitter. I guess the regs have changed since then because I’m pretty sure it complied with the regulations at the time.

[Chris_in_the_UK]

It was installed in 2015 by an approved charger fitter. I guess the regs have changed since then because I’m pretty sure it complied with the regulations at the time.

Regs changed 1st Jan 2016 - from then on the consumer unit should be metal cased.

[Bonzodog]

I installed a 10 mm three core Swa ready for a future charger.

[Kingstepper]

I’d be putting this in, dependant on run length and load. The cable has an integrated cat 5 within it for the smart metering communication part of the charger.

https://www.toolstation.com/cut-to-l...r-cable/p82520


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Might work in your case but surely only useful if router etc. is adjacent to the consumer unit.

[Boss13]

Thanks all for the helpful info. Must admit cannot get my head around the cat 5 requirement!

I believe we are having two new consumer boxes. I will ensure there is a 32a breaker spare and attach something along the lines of below based upon post above.

https://www.tlc-direct.co.uk/Products/SW10slash3.html

Sounds like that will cover it?

Keen to get this done as consumer units are going to be closer to middle of house than the external walls which means not ideal for future fitting.

[adrianw]

It was installed in 2015 by an approved charger fitter. I guess the regs have changed since then because I’m pretty sure it complied with the regulations at the time.

Not sure when 17th edition came out but pretty sure it was before then so should still have been an RCBO

[Pennywise]

There isn’t any requirement for the supply pictured to be protected by an RCD as it’s clipped direct and is wired in SWA, the RCD protection will be integrated into the charger point so still has the required level of protection for the unit.

The cat 5 is for the charger point to communicate with the CT clamps at the supply head, this allows the charger to see the level of consumption in the rest of the house and change the charging rate accordingly. Some charger points require hard wired connections other newer versions use a Wi-fi enabled monitoring device. It just covers all bases.


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[adrianw]

There isn’t any requirement for the supply pictured to be protected by an RCD as it’s clipped direct and is wired in SWA, the RCD protection will be integrated into the charger point so still has the required level of protection for the unit.

The cat 5 is for the charger point to communicate with the CT clamps at the supply head, this allows the charger to see the level of consumption in the rest of the house and change the charging rate accordingly. Some charger points require hard wired connections other newer versions use a Wi-fi enabled monitoring device. It just covers all bases.


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Pod point fitted an RCBO at the supply end of the armoured cable they fitted, it’s is about four metres long, as did we for all of our kitchen appliances

[Dave+63]

There isn’t any requirement for the supply pictured to be protected by an RCD as it’s clipped direct and is wired in SWA, the RCD protection will be integrated into the charger point so still has the required level of protection for the unit.

The cat 5 is for the charger point to communicate with the CT clamps at the supply head, this allows the charger to see the level of consumption in the rest of the house and change the charging rate accordingly. Some charger points require hard wired connections other newer versions use a Wi-fi enabled monitoring device. It just covers all bases.


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It is RCD protected.

[Pennywise]

It is RCD protected.

Perfect so has a higher protection rating than required always nice to have





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[Pennywise]

Pod point fitted an RCBO at the supply end of the armoured cable they fitted, it’s is about four metres long, as did we for all of our kitchen appliances

If that’s the way they do it that’s fine, just not an absolute requirement if wired in SWA, the kitchen appliance of course will require it as most likely they’ll be presented as a socket outlet that would need RCD protection regardless of wiring type.


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[adrianw]

If that’s the way they do it that’s fine, just not an absolute requirement if wired in SWA, the kitchen appliance of course will require it as most likely they’ll be presented as a socket outlet that would need RCD protection regardless of wiring type.


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Surely the difference between an RCD and an RCBO is that it is double pole so monitors current rather than just leakage and are being phased in for all applications, and one thing an electric car can do is draw current.

[Sweepinghand]

Just as you say pay a d get a proper approved job done by a correct qualified installer
You won’t get the grant but you’re looking to futureproof the property right?
Tbh if folk are just using the 3 pin chargers with the cars (I have fir 12 months) and outside normal covered so key is also an option - and gives an extra charging point too should you then go electric and take advantage of the scheme


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[Pennywise]

Surely the difference between an RCD and an RCBO is that it is double pole so monitors current rather than just leakage and are being phased in for all applications, and one thing an electric car can do is draw current.

RCBOs are a nice to have not a requirement, the supply to the charge point in the pic is still protected from overload and short circuit via the MCB. As for double pole, rcbos are not normally they are single pole which is actually only a reference to the terminals and if they are both isolated when the RCBO is in the off position


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[Dave+63]

Surely the difference between an RCD and an RCBO is that it is double pole so monitors current rather than just leakage and are being phased in for all applications, and one thing an electric car can do is draw current.

They can either draw 16amps or 32amps on single phase so no more than a domestic cooker.

Obviously, 3 phase supplies allow a greater draw on cars designed to take 3 phase.

[julian2002]

What can happen if you have a plastic box



This was about 2 months after a professional installation.

[Tooks]

Electrician fitted a 32A RCBO to a spare slot in our consumer unit, then ran suitably sized armoured cable to the charge point.

There’s no requirement for a Cat 5 cable unless it’s being grant funded or you have a low Amp main supply and will be fitting an EVSE that does load monitoring.

Our Car EVSE actually plugs into a Switched 32A CEEFORM socket (it’s an OHME unit) but the electrician quite rightly treated and fitted it like a dedicated EV charge point, including fitting an earth rod at the 32A switch end.

For future proofing purposes then, I’d just make sure you have a spare slot in your metal consumer unit, and a 100A supply.

You can run the cable out to a suitable location when you’re ready unless you have use for a 32A Commando socket in the same place.

[adrianw]

They can either draw 16amps or 32amps on single phase so no more than a domestic cooker.

Obviously, 3 phase supplies allow a greater draw on cars designed to take 3 phase.

My comment was a bit flippant, I meant under fault conditions, we have a 93kw electric car, under the wrong circumstances it could draw a lot of current.

[Xantiagib]

Google zappi charger installations, they don't need an earth rod and you can use wifi or integrated cat5 cable if you wish
I've seen many in anticipation of having to do similar, but found these guys explained things quite well: https://youtu.be/oV9_aGgv92c

they also have vids about connecting to existing consumer units and what to do if you have a looped supply.

[adrianw]

Google zappi charger installations, they don't need an earth rod and you can use wifi or integrated cat5 cable if you wish
I've seen many in anticipation of having to do similar, but found these guys explained things quite well: https://youtu.be/oV9_aGgv92c

they also have vids about connecting to existing consumer units and what to do if you have a looped supply.

Massive lack of detail in that video.

[Xantiagib]

Massive lack of detail in that video.

true for most youtube videos... you need to watch all the videos in the series then at least you get some sort of an idea - watching others just got me more confused

[jaytip]

Sorry to hijack this thread. I’m now looking at electric cars and having a garage and drive, I would look to have a home charger installed. I don’t know anything at all about electrics, so could someone more knowledgeable than me tell me if my power source is adequate?
My garage is at the top of my garden so I would guess a run of about 20 odd meters. If the current cable isn’t thick enough to carry the load, would the grant cover the cost of running new cable that distance or is it something I would have to cover?
Cheers.

[Tooks]

With that sort of cable run, most installers will class it as a non standard install, and it will cost more.

To be fair, the grant will only cover about 30-50% of one of the big installers prices anyway.

I can’t really comment on your garage consumer unit, but for a 7.2kW charger, you’re basically looking at a 32A feed from your consumer unit to the place where the charging equipment will be installed. You’ll also need a means for the charging unit to communicate with big brother to send usage data etc, which is a condition if you want the grant.

A cheaper alternative way to do it is to sign up to Octopus or similar, and purchase a subsidised Ohme unit for £199. You then pay a local electrician to install the 32A cable terminating in a 32A switched CEEFORM socket that the Ohme unit plugs into. They should ensure it’s compliant with current regs.

I purchased an Ohme unit independently and paid a local electrician to install the Commando socket 30m away, and I’ve also housed the unit in an enclosure. All in cost was about £650, which was still far less than PodPoint etc wanted for an install even after grant, and I don’t have to have the connectivity either.

[mk2driver]

Your garage feed is very unlikely to be sufficient - mine wasn’t and I ended up with a 25m run

The grant is just off a standard install so anything above that you cover the cost

[jaytip]

With that sort of cable run, most installers will class it as a non standard install, and it will cost more.

To be fair, the grant will only cover about 30-50% of one of the big installers prices anyway.

I can’t really comment on your garage consumer unit, but for a 7.2kW charger, you’re basically looking at a 32A feed from your consumer unit to the place where the charging equipment will be installed. You’ll also need a means for the charging unit to communicate with big brother to send usage data etc, which is a condition if you want the grant.

A cheaper alternative way to do it is to sign up to Octopus or similar, and purchase a subsidised Ohme unit for £199. You then pay a local electrician to install the 32A cable terminating in a 32A switched CEEFORM socket that the Ohme unit plugs into. They should ensure it’s compliant with current regs.

I purchased an Ohme unit independently and paid a local electrician to install the Commando socket 30m away, and I’ve also housed the unit in an enclosure. All in cost was about £650, which was still far less than PodPoint etc wanted for an install even after grant, and I don’t have to have the connectivity either.

Sounds like a good solution. Thank you.

[Dave+63]

My comment was a bit flippant, I meant under fault conditions, we have a 93kw electric car, under the wrong circumstances it could draw a lot of current.

Not going to happen with a 32amp breaker at the box.

[MB2]

Not going to happen with a 32amp breaker at the box.

I think the maximum current my cars AC/DC convertor can handle is 16 amps so presumably that would also fuse/turn off ?

[Dave+63]

I think the maximum current my cars AC/DC convertor can handle is 16 amps so presumably that would also fuse/turn off ?

My van will only charge at 16amps too but most of the new EVs are now 32amp (7kw), particularly those with larger batteries.

There are probably multiple failsafes as well as the breaker in the consumer unit.

[adrianw]

My van will only charge at 16amps too but most of the new EVs are now 32amp (7kw), particularly those with larger batteries.

There are probably multiple failsafes as well as the breaker in the consumer unit.

I’ve seen the circuit diagrams for both ends, the only safety devices are to make sure both ends of the charge lead are connected before it can turn on, most of the electronic devices in the pod point are for communications.

I think most new vehicles are capable of 11kw three phase charging.

Under fault condition vehicles are easily capable of drawing more than 32amps, in time we will see failures in the same way any mass produced battery products do.

One thing to consider, if the batteries do catch fire it is very difficult to extinguish, sometimes impossible, I wouldn’t have one near the house or in the garage, ours is well away.

[Bravo73]

Any tips on what should be done, i.e. which wire, which fuse, etc.?

This is worth watching (along with a lot of his other vids re EV chargers):

[Dave+63]

I’ve seen the circuit diagrams for both ends, the only safety devices are to make sure both ends of the charge lead are connected before it can turn on, most of the electronic devices in the pod point are for communications.

I think most new vehicles are capable of 11kw three phase charging.

Under fault condition vehicles are easily capable of drawing more than 32amps, in time we will see failures in the same way any mass produced battery products do.

One thing to consider, if the batteries do catch fire it is very difficult to extinguish, sometimes impossible, I wouldn’t have one near the house or in the garage, ours is well away.

Some cars have three phase 11kw or 22kw capability but most are 3.6kw or 7.2kw single phase along with DC rapid charging. I could be wrong though and they’re all capable of three phase charging even though it’s largely irrelevant in the UK.

Whilst you say that the car could draw more than 32amps which, not being an electrician, I can’t argue with, the 32amp breaker at the consumer unit should prevent this from happening. Kitchen hobs draw a similar current and nobody seems to have issues with them?

Batteries can catch fire but it seems that they are almost impossible to ignite accidentally these days; a tank full of petrol would be much easier.

[demonloop]

I'm doing a new build soon, but no plans for an EV just yet, so I'm just ducting back to the consumer unit and will sort the correct cable come the time

[adrianw]

Some cars have three phase 11kw or 22kw capability but most are 3.6kw or 7.2kw single phase along with DC rapid charging. I could be wrong though and they’re all capable of three phase charging even though it’s largely irrelevant in the UK.

Whilst you say that the car could draw more than 32amps which, not being an electrician, I can’t argue with, the 32amp breaker at the consumer unit should prevent this from happening. Kitchen hobs draw a similar current and nobody seems to have issues with them?

Batteries can catch fire but it seems that they are almost impossible to ignite accidentally these days; a tank full of petrol would be much easier.

It is illegal to ship a charged lithium battery on an aircraft (passengers can have them) yet you can pump electricity into them in or by your house, there will be accidents, the legislation will be put into place.

[Dave+63]

It is illegal to ship a charged lithium battery on an aircraft (passengers can have them) yet you can pump electricity into them in or by your house, there will be accidents, the legislation will be put into place.

The onboard charger is a maximum of 7kw and the consumer unit has a 32amp trip, why are you so sure that the battery will somehow be over charged such that it’s going to bypass all the fail safes and spontaneously combust?

[adrianw]

[QUOTE=Dave+63;5816720]The onboard charger is a maximum of 7kw and the consumer unit has a 32amp trip, why are you so sure that the battery will somehow be over charged such that it’s going to bypass all the fail safes and spontaneously combust?[/QUOTE

The failsafes are, battery temperature and voltage thresholds, my comments are concerned with fault conditions, as I said earlier cars will catch fire, I haven’t got the MTBF data but I could get it, if they were completely safe they the aircraft rules would be different.

[Dave+63]

Even the MTBF figures wouldn’t give accurate data on the numbers or percentages of those failures ending up in a catastrophic fire.

The aircraft rules are in place for safety reasons granted, but aircraft safety is set at a much higher level than most other situations and the conditions in which the batteries would be carried (depressurised hold) are substantially different to those at ground level.

I think we can safely discount the air industry rules as holding little or no relevance to ground level EVs.

You may disagree though and that’s fine, we’ll just have to agree to differ on our perceptions of the dangers involved.

[Boss13]

Called pod point today who said they use 6mm 3 core SWA. Up to 50m lengths then 10mm above that. So I will be laying a 6mm.

They also mentioned they need the data cable cat 5 from the charger to consumer unit too. As a poster above highlighted. I will lay this too.

Just in case anyone else was interested in what I think may possibly be the correct answer. For a 7kw charger btw.