UK Cabling for future EV charge point

[loldollard]

Hi all,

I am currently tidying up our front garden and want to bury some underground conduit to provide a cable route for an ev charge point sometime in the future (don't fancy digging up the lawn and path again).

My electrician has suggested 6mm swa cable should allow for a decent powered charger (please confirm). I think it might be easier to lay the cable at the same time due to its size but wanted to check if I should pull any other cables also?

I have noticed that some of the EV charging units need control / coms wires to communicate with a panel in the house etc. I have seen electricians use ethernet cable.

So I guess my question is.. if you were laying cables for a future install, what would you put in to cover all possibilities?

I think it was the zappi that needed coms wires. I do wonder if in a couple of year's time the tech has advanced further.

Thanks in advance

 

[ChipFanDave]

It's almost impossible to say without any information on the distances or layout of your individual circumstances.

If possible could you give a indication of what sort of route you think it may need along with a semi-decent sketch/plan drawing.

 

[Spoon]

Welcome to the forum mate.
If you don't know what charger you are going for why not just put the conduit in and leave the cabling to when you pick a charger? Put a pull cord in the conduit and no sharp bends.

 

[Taylortwocities]

Use twin wall "civils" ducting. It comes with a draw cord.

 

[loldollard]

Thank for the replies!

I'm probably overthinking it a bit with so many unknowns. I suppose my main concern was pulling such a chunky cable through ducting.

I've spotted the twin wall conduit with smooth inner (thanks for the tip). Do you think the 50mm ID version will be adequate?

I've seen electricians in the past replace the supplied pull cord with some tougher rope, do might do that. What sort of bend radius is the limit before it would become an issue?

The run in conduit will be 7m where it enters the house then a further 13m under the floor to the CU.

 

[hasel5]

If you could get the 50mm duct from where you want the Charge point to the cu in one length that would be the ideal situation.

You will then have the options on both cable size and data cable
Normally the string in the duct is pretty good to pull in on.
Just make any bend as slight as possible

 

[pc1966]

A quick look in the IET On Site Guide shows 6mm cable as potentially good for a 40A circuit to 46m length so you could get up to 9kW charging.

If you have a draw string in the duct then it can be used to pull through a stronger rope later as needed. Bend radius limit is typically 8-10 times the diameter of the cable, pipe, etc, so that would imply around 0.5m minimum for the duct but as already mentioned you want it as gentle bends as practical.

There is no hard and fast rule about burial depth, but obviously it has to be deep enough not to be damaged by any likely activity such as future gardening, etc. While it is not a requirement for your duct as such, the minimum depth that most power companies work to is 45cm (but often deeper) so that would be a reasonable value. Worth checking with your electrician though in case they have any particular views to take in to account.

Where the duct rises to the potential location of the power point it would be more vulnerable, so depending on the specific layout you might consider putting a paving slab over there or similar to ensure no digging too close to it.

 

[loldollard]

Perfect...thanks!

The ducting will break ground through a small concrete slab so I will make sure the ducting stays well below the surface to this point. It's a 1m long slab so will be able to get a gentle radius on the ducting.

Thanks everyone, much appreciated.