Cable from CU to EV charger

[AVI_8]

Distance from house CU to where the wall charger is around 30 metres, I’ve had a look at a cable size calculator and it seems to show that a 6mm SWA is fine, cable running under solum and clipped externally.
The charger I’m going to get is a Hypervolt, their installation manual says that for longer runs 10mm is preferred, it also says a CT clamp is necessary so presumably that means 3 core plus a data cable all within the SWA, It also states a dedicated CU with 40 amp double pole RCBO which I’ll get as I don’t have any spare ways otherwise, the CU in my house which supplies the workshop has a spare 40 amp MCD but from what I’ve researched this is not correct for the job and this CU already has a 10mm SWA going to it and doesn’t leave much room for another.
So 32 Amps, 30 metres, what’s acceptable 6mm, clearly 10mm would be preferable but I don’t want to spend more than is necessary.

 

[addjunkie]

Get the person fitting the charger and signing it off, to spec the cable, some chargers need both internet and CT

 

[knighty]

power and data combined cable makes a much tidier install

6mm

Electric Vehicle Charging Cable Power & CAT5e | EV-ULTRA | 3 core 6mm² | Black | Superlec Direct

This cable is for use in the installation of electric vehicle charge points. This is a combined 3 core 6mm² power and 4 pair CAT5e Data cable in a double sheathed design for extra protection.

www.superlecdirect.com

10mm

Electric Vehicle Charging Cable Power & CAT5e SWA Armoured | EV-Ultra | 3 core 10mm² | Black | Superlec Direct

This cable is for use in the installation of electric vehicle charge points. This is a combined SWA armoured 3 core 10mm² power and CAT5e Data cable in a double sheathed design for extra protection.

www.superlecdirect.com

 

[knighty]

also, how much of the cable will be inside/through walls/in insulation etc. etc.

 

[AVI_8]

also, how much of the cable will be inside/through walls/in insulation etc. etc.

I’ll all be inside routed under the floor in free air apart from the last 4 metres which will exit through the wall, no insulation and around a corner into the EV charger clipped to the wall, so I think I’m correct in saying that it doesn’t have to be steel wired unless it’s buried, thanks for the links, EV Ultra seems to be what the installers on you tube are using, 3 core and cat 5e for the CT clamp signal, this charger is capable of using Wi-Fi, and will be through the wall 3ft from my router, that’s the reason for the long cable run.

 

[Onoff]

This is the spec for my charger:

My charger is 37m from the house cu. I have 24m of 16mm² SWA run underground in duct from house cu to garage cu then 13m of 10mm² SWA from garage cu to EV charger that's clipped direct. Luckily I had the cables already.

At the house I have a 60A switch fuse with a 100mA Type S RCD. That feeds the 16mm² SWA to the garage.

The "breaker" for the EV charger is in the garage cu. It's a 40A, DP, C curve, bidirectional RCBO. That feeds the 10mm² to the EV charger.

I ran a Cat-6 duct grade cable separately from the EV point back to the house. The green and orange pairs are used for internet, the blue pair for the CT transformer and the brown pair spare.

 

[J1nx]

I have the Hypervolt and it’s definitely worth connecting via Ethernet rather than the WiFi, I didn’t as the router was literally the opposite side of the garage wall (not even insulation between them) and it would drop out, pulled in a cable last month and been solid so far.

 

[angellonewolf]

i know pulling in a larger cable will put the cost up a bit 50 or 80 quid? but the cable is not the expensive part of the install and the larger cable could mean if you change or up grade at any point you have the larger cable all ready there

i was glad years ago i put in a 10mm cable for a shower install could have got away with 6mm but put in 10 but years later the shower failed i put in a 10.5 kw shower as i had the cable there all ready for it

 

[Onoff]

I assume these extracts are from the Hypervolt manual you're reading?

Have you a photo of your existing cu?

 

[hotponyshoes]

Looking at the rapid rate ev charging speeds are increasing I'd say run the biggest cable you can as you may well find your next car needs double the power of this one.

Or hydrogen might take over then you could use the garage to house a big welder / laser cleaner / induction heater!

 

[8ob]

We have done civils for hundreds of ev chargers, we only do as we are told but can confirm they always get us to run in 16mm cable and the ones that are a long way from the power source are 25mm. Don’t ask me anything tech on this, we do the concrete bases and run the service coz we iz fick

Bob

 

[AVI_8]

I assume these extracts are from the Hypervolt manual you're reading?

View attachment 527813

View attachment 527814

Have you a photo of your existing cu?

Thanks all for your advice as usual, yes @Onoff that was the instructions I was looking at.

Apparently the voltage drop from a 6mm cable would be 9v and for the 10mm would be under 3 so yes it’s a bit of a no brainer to lay the 10mm for the sake of another £90

By the way I’m not connecting anything just fitting the meters and laying cable, I’ll get the spark who connected my workshop out to connect everything and sign the paperwork.

Here’s a picture from my electric cupboard, the house was 3 phase when we moved in but was re wired single phase in 2015, new plastic CU at the time, the other smaller CU was added a few years ago and is supplying the workshop via a 10mm SWA

There is space for a dedicated EV CU to thd right of the meter which is what I was planning, it’ll just need more tails.

On the big box at the bottom right of the picture where the supply comes in I presume that’s where the fuse is, it’s not stamped anywhere the size of the fuse on that box, I presume 100 amps, the only thing marked 100 amps is the is the box with tails that the spark who fitted the workshop CU fitted but I’m guessing that’s just a max load stamp.

I have the Hypervolt and it’s definitely worth connecting via Ethernet rather than the WiFi, I didn’t as the router was literally the opposite side of the garage wall (not even insulation between them) and it would drop out, pulled in a cable last month and been solid so far.

Was that just an Ethernet extender cable from the router to the EV charger?
I could do that the alternative would presumably be to run an Ethernet extender 20 metres under the floor to the EV CU from the router and get the spark to wire it to the supply cable, or is that not how it works, does that mean I’d need a 10mm supply on a Cat5e or Cat 6 cable.

Actually if I was doing that and having hard wired internet I’d be as well to fit the charger to the wall at the other side of the house which would be a 10 metre cable run from the CU to EV charger, this now seems to be a more sensible option.

Yes I’ll definitely be speaking to the spark before ordering the cable but I like to have things clear in my head before I do so.

 

[J1nx]

Yes just plugged straight into the router mate, normal patch cable, i just made it upto length.

Think I ran a separate pair, like a belden cable or similar in originally for the CT. My CT isn’t on the main incomer just back to a local board but that’s due to a strange setup with my house battery and solar inverter locations.

If in doubt you can run two Cat5e’s in as the cost is sod all but always nice to have a fail safe. Or run in the EVultra plus a separate cat5.

 

[daedalusminos]

Most home EV chargers have built in PEN fault protection - which is likely to be triggered if the supply falls outside the acceptable tolerance (230 +10%, -6% - 216V to 253V). If your supply is on the low side coming in then excessive volt drop on the SWA could cause issues.

 

[AVI_8]

Most home EV chargers have built in PEN fault protection - which is likely to be triggered if the supply falls outside the acceptable tolerance (230 +10%, -6% - 216V to 253V). If your supply is on the low side coming in then excessive volt drop on the SWA could cause issues.

Yes this charger has that, so 10mm it is

 

[Turbo]

I should imagine that the swa and cat 5 combined cable is a lot more expensive than std swa.
Probably work out cheaper to run 2 separate cables and if there is a fault in either cable you only have to replace 1.
For neatness try to run it in trunking.
If you are not going underground could you use hi-tuff cable? It's a lot cheaper than swa.

 

[AVI_8]

I should imagine that the swa and cat 5 combined cable is a lot more expensive than std swa.
Probably work out cheaper to run 2 separate cables and if there is a fault in either cable you only have to replace 1.
For neatness try to run it in trunking.
If you are not going underground could you use hi-tuff cable? It's a lot cheaper than swa.

Yes I’ve seen that EV Ultra, it’s re enforced but not SWA, should be good enough as it won’t be buried.

 

[Turbo]

I said hi tuff not ev ultra!

https://www.electrical4less.co.uk/2...pQlrCbt654PLcwAmyIigKhBS-btqw-5NxM23wR4tPi0Ez

It can be used outside and is a lot easier to install than armoured cable.

Hi tuff is £6 per metre
Exterior grade cat 5e is £1 per metre
All in 1 Ev Ultra is over £10 per metre

By using 2 standard cables instead of 1 special cable it is significantly cheaper. Then if you need to upgrade to cat 6 cable in the future or there is a fault in the data cable you only have to replace 1 cheap cable instead of the whole thing!

 

[AVI_8]

I said hi tuff not ev ultra!

https://www.electrical4less.co.uk/2...pQlrCbt654PLcwAmyIigKhBS-btqw-5NxM23wR4tPi0Ez

It can be used outside and is a lot easier to install than armoured cable.

Hi tuff is £6 per metre
Exterior grade cat 5e is £1 per metre
All in 1 Ev Ultra is over £10 per metre

By using 2 standard cables instead of 1 special cable it is significantly cheaper. Then if you need to upgrade to cat 6 cable in the future or there is a fault in the data cable you only have to replace 1 cheap cable instead of the whole thing!

Ok thanks for the link

 

[premmington]

Most home EV chargers have built in PEN fault protection - which is likely to be triggered if the supply falls outside the acceptable tolerance (230 +10%, -6% - 216V to 253V). If your supply is on the low side coming in then excessive volt drop on the SWA could cause issues.

I had issues with this at my workshop - incoming was low 218v at times. When fitting EV chargers for working on customers cars

Ended up finding out who my DNO was - to be honest - they came had a chat - did a survey. 9/10days later it's a steady 234.6v

Unsure what they did - to this day I have no idea....?

Every few months a van turns up - chap gets out - takes a voltage measurement and goes.

Concidering I was told the lowest reading allowed is 216.2v - I got good service to be honest.