Cable run for car charger

[ScottishGasMan]

Hey all.

Looking at potentially getting electric car next year and nearly ready to put floor down in my hall.

At the moment my CU is about 2.5-3m away from the outside wall where I would have a charger fitted, but I need to dig a bit outside and feed either a cable or conduit under the ensuite in between the CU and outside wall before I put floor down to avoid lifting it all back up later.

Question is: is it more likley an electrician would use SWA directly to charger or T&E in a conduit to a gland on them? I've seen charger installs but never paid much attention to them, cable would have to come out at low level and surface run upto height of charger, and ideally I'd like to not have a junction box on show just under it.

but not sure if SWA can terminate directly into typical car chargers or how its done.

I suppose I could run conduit anyway and they could run whatever they want through it, but I've typed this much so may as well ask!

If it make any odds would be a 7kw charger so I'd imagine 6mm cable

 

[ScottishGasMan]

Actually while thinking about it. The electric meter is in a cupboard in the bedroom which is on an external wall, cables from the meter go into an isolator switch, then armored from there under floor to CU which is in hall cupboard.

Would they be able/allowed to split the cable in electric meter compartment, fit an MCB there and then have cable direct through wall to outside without going through the main CU? Looking at the Zappi charger so has built in RCD to cover the install if SWA is used.... I think.

 

[ericmark]

EV charging is complex, there are three major problems.
1) Overloading system, often there is a current monitor to reduce charging rate if other items are putting a heavy load on the system.
2) Freezing of the RCD under fault conditions, either a type B RCD or a DC current monitor so it trips if over 6 mA of DC.
3) Earthing system, only a problem with TN-C-S or PME earthing, but where that is used for house, either voltage monitor (207 to 253) or a reference earth rod, or converting the system to TT or even an isolation transformer may be required.

The result is the electricians has to do a risk assessment, and being too close to home is as much of a problem as too far away, he has to select a charging pod which is best for your house, there is no one type fits all. In my house he can fit the charging point some 20 meters from house, so he can sink an earth rod and install a TT system. Or I can convert my flat back to a garage and charge the car indoors, and use the PME supply.

My sons house there is a problem as the meter cupboard too close to drive, so likely he would need a special charging pod.

So until the installer has designed the system can't answer your questions.

 

[SUNRAY]

EV charging is complex, there are three major problems.
1) Overloading system, often there is a current monitor to reduce charging rate if other items are putting a heavy load on the system.
2) Freezing of the RCD under fault conditions, either a type B RCD or a DC current monitor so it trips if over 6 mA of DC.
3) Earthing system, only a problem with TN-C-S or PME earthing, but where that is used for house, either voltage monitor (207 to 253) or a reference earth rod, or converting the system to TT or even an isolation transformer may be required.

The result is the electricians has to do a risk assessment, and being too close to home is as much of a problem as too far away, he has to select a charging pod which is best for your house, there is no one type fits all. In my house he can fit the charging point some 20 meters from house, so he can sink an earth rod and install a TT system. Or I can convert my flat back to a garage and charge the car indoors, and use the PME supply.

My sons house there is a problem as the meter cupboard too close to drive, so likely he would need a special charging pod.

So until the installer has designed the system can't answer your questions.

However if you have the floor up, the cost of laying in a 50mm duct is minimal.

 

[bsr]

You will probably need ethernet cable as well as power (most 7KW chargers now use a clamp ammeter to measure whole house current and avoid overload) so either lay power and data, or as Sunray said, put a duct and two drawstrings.

 

[plugwash]

Potentially you could end up wanting two "CAT" cables, one for CT connections and one for data communications (either to the EV charger itself or to a wireless access point located near it). I guess you could use different pairs in the same cable for that but it seems rather hacky.

 

[SUNRAY]

Potentially you could end up wanting two "CAT" cables, one for CT connections and one for data communications (either to the EV charger itself or to a wireless access point located near it). I guess you could use different pairs in the same cable for that but it seems rather hacky.

'EV' cable now includes a data cable.

 

[JohnD]

'EV' cable now includes a data cable.

the tech is at such an early stage that I'm sure it would be best to run the cable in oversized conduit, or trunking that you can open for later changes.

 

[plugwash]

'EV' cable now includes a data cable.

Doncaster's EV Ultra cable comes in variants with either a single twisted pair or a CAT5e quad twisted pair. Dunno about other manufacturers.

In principle I guess you could use some pairs in the CAT5e for Data and some for CTs but it feels wrong to me. I have no idea how well the CT circuits in an EV charger are isolated from the mains and terminating only some of the pairs of a data cable to a "RJ45" plug can be a bit of a pain.

Also some chargepoints are now wifi only, so the Data would need to go to an access point near the charger, not to the charger itself. Similarly you may want a wifi access point near the charge point to provide data service to the car itself.

I'm inclined to agree with John that a duct is a good option where practical.