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Discussion Starter #1 (Edited)
Hi

My home charger is going to be on a wall outside my house meaning the cable will need to run under a block paved drive. I'm planning to get the work done before British Gas come to fit the 32A unit so they don't have to make 2 trips with 4-6 weeks delay in between.

Can anybody tell me what kind of cable should be used? 32A for a 32A supply our does the cable need to have a higher design load rating, eg. 10mm2 ? Armoured? How deep?
I presume there are regulations for this sort of thing?

Thanks in advance for any guidance.


 

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Driving yet another EV!
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The cable choices are based on a number of factors, mainly where it is being installed (underground, in a wall, in a loft, clipped to the outside of a wall etc.) and how far it runs from the consumer unit (fuse box) to the final outlet (i.e. the EVSE). There are written rules covering these factors, but a good starting place is here:

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

However - you will also need to ensure that it is installed correctly - which means in this case 600mm (about 2 feet) below the surface, on top of a decent bed of suitable material (such as sand) and with the correct warning tape buried above the cable to warn diggers. I would recommend this work being done by someone with experience of installing underground cables. You will also need to be able to satisfy the BG installer that this has been done correctly as it is his responsibility if it isn't and he has to sign a document stating that it is correct. If he is not happy he will not sign off and it will be illegal to use the EVSE. Photos of each stage of the work being done should be enough to satisfy him.
 

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Discussion Starter #3
Thanks, the total run will be about 12m, of which only 3 is underground, (so 4 given the 5-600mm drop). Presumably only the underground section needs to be SWA, as the rest can be in conduit, with metal junction boxes for the gland connections. The BG chap can then run the cables to and from either end. I'm wondering whether a 32A EVSE actually draws more and hence what diameter the 4m SWA cable needs to be?
 

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Driving yet another EV!
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It sounds like the underground run would be fine with 6mm PVC SWA or 4mm XLPE, terminated at each end in a suitable waterproof box such as:

http://www.tlc-direct.co.uk/Products/LB9065.html

There will be other considerations depending on the exact layout and the way that the unit is going to be installed - for example should the SWA run for the whole external length, or just under the drive. You probably should discuss the requirements with either the installer or the person that is going to do or has done the site survey.
 

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Discussion Starter #5
Yes, that's the thing, British Gas don't do a separate site survey: you have to call them; they promise to call you back in 2 weeks; (they don't,) then they take payment and schedule the visit for 3-4 weeks later, expecting to do the job that day. If they can't or won't they tell you what needs doing and the booking process starts again.

Thanks
 

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4mm 3 core swa will do a run up to 15m in length. 600mm down like Matt said if your going to bury it. They will need to rod it if it's an external location and also do a risk assessment on any conductive items that are within 10ms - gas pipes class I light fittings etc.
Take it your experience with BG hasn't been smooth as yet? You not find a local installer who may be able to help? Where you located may be able to find someone for you.
 

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Discussion Starter #7
I'm in Wimbledon. Unfortunately "local" installers seem to have fallen foul of the grant freeze, whereas BG day they're honouring orders registered.
 

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Confirmed with BG for tomorrow with their PH division. I thought it was today but it's tomorrow. Fingers still crossed. I guess if they have applied for the paperwork in advance it might just go through.
 
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