Advice on cable for EV Charge Point Cable

[tvrulesme]

Just taken deilvery of an Electric Car (Mini Electric) and so doing some research into installing a charge point.

Supply is a standard Single Phase and I have appointments booked with my supplier and DNO to upgrade meter tails and cutout fuse respectively.

I'll get a spark to do all the connections but looking to run the cable myself to save a few ££.

In terms of the cable it looks like I have a few options so just looking for advice. The run is 28m and will be clipped direct under kitchen cabinets before exiting the exterior wall and going up and over a side extention to our driveway clipped to the exterior brickwork.

Chargepoint specs are:

• Rated power: Up to 7.2kW
• Charging current: 6A to 32A (variable)
• Rated current: Up to 32A max
• Nominal supply: 230VAC 50Hz
• Supply connections: L1, N, PE 2.5 - 10mm2
• Internet connection: Home Wi-Fi (2.4GHZ only) or a CAT5 Ethernet cable to Home LAN (Ethernet-USB Adaptor required)

A quick look at a voltage drop calculator shows me that 4mm would within range

Required Cable Size	4mm
Voltage Drop	8.77 Volts
Percentage Drop	3.8%
Current Load	31.3 Amps
Max Cable Load	42.0 Amps

So my choices are (with prices):

1. EV Ultra Cable - PVC Tuff-Sheathed - £164.64
2. EV Ultra Cable - SWA Cable 3 Core - £188.16
3. Seperate 4mm SWA + Shielded outdoor CAT6 - £101.51

Questions are:
Is there any reason to consider oversizing the cable to 6mm or 10mm?
If money was not an object (it clearly is) does EV Ultra give me anything other than convenience?
Would the regs allow me to use PVC Tuff-Sheathed clipped to an exterior wall or does it have to be armoured?

 

[davesparks]

You need to speak to the electrician before you start.
There are specific regulations covering EV charge points which need to be complied with.

The electrician will make their own decision about cable size and type, and will be able to tell you how much or how little of the work they are happy for you to do.

No decent electrician is going to accept liability for connecting up a cable which has been specified and installed by someone else without prior discussion.

 

[tvrulesme]

You need to speak to the electrician before you start.
There are specific regulations covering EV charge points which need to be complied with.

The electrician will make their own decision about cable size and type, and will be able to tell you how much or how little of the work they are happy for you to do.

No decent electrician is going to accept liability for connecting up a cable which has been specified and installed by someone else without prior discussion.

Thanks Dave. I get what you're saying but I'm just at the stage of doing research and will speak to electrician's before I spend my pennies or drill any holes but this is a forum to discuss things right?

In terms of specific regulations for private electric vehicle smart charge points I can only see reference to "the ability to send and receive information, the ability to respond to signals to increase the rate or time at which electricity flows through the charge point" which would be taken care of with the CAT5/6 cable.

The rest would be down to voltage drop and the usual regs concerning any outdoor cables installation. As Doncaster Cables who manufacture both the SWA and the EV Ultra state the Voltage drop (mV/A/m) to be identical between the two, really wondering if EV Ultra would offer any further benefits?

 

[JBW175]

It’s not just VD you have to think about.

Earthing arrangements, EFLI, meeting disconnection times etc…

Get an electrician in and let them do a proper cable calc.

 

[tvrulesme]

It’s not just VD you have to think about.

Earthing arrangements, EFLI, meeting disconnection times etc…

Get an electrician in and let them do a proper cable calc.

As an update I did what I was told and got an electrician in. Earthing rod seemed like a bit of a fudge so we decided that a charger with PME protection was the answer so going for the Wallbox Pulsar Plus which has Built In Earthing (for the 7,4kW version).

SWA cable not required but a suggestion to upgrade to 6mm seemed sensible given the 3.8% voltage drop over 28 meters.

So question remains whether I go for EV Ultra or a combination of NYY-J and outdoor grade CAT6. Price difference is significant

EV Ultra 6mm x 28m @£8.10 p/m = £226.80

or

6mm 3 Core NYY-J x 28m @£3.95 p/m = £110.88
50m CAT6 = £21.99
Total = £132.87

So if money was not an object (it clearly is) does EV Ultra give me anything other than convenience?

 

[JBW175]

As an update I did what I was told and got an electrician in. Earthing rod seemed like a bit of a fudge so we decided that a charger with PME protection was the answer so going for the Wallbox Pulsar Plus which has Built In Earthing (for the 7,4kW version).

SWA cable not required but a suggestion to upgrade to 6mm seemed sensible given the 3.8% voltage drop over 28 meters.

So question remains whether I go for EV Ultra or a combination of NYY-J and outdoor grade CAT6. Price difference is significant

EV Ultra 6mm x 28m @£8.10 p/m = £226.80

or

6mm 3 Core NYY-J x 28m @£3.95 p/m = £110.88
50m CAT6 = £21.99
Total = £132.87

So if money was not an object (it clearly is) does EV Ultra give me anything other than convenience?

You’re lucky that you’ve found a sparky that’s willing to let you carry out all the design considerations.

Normally when I’m employed to do a job,

I design it myself, install it myself, I&T it myself.

I’d ask your sparky what they’d recommend, as they’re the one that’s got to work with it, pull it in, secure and terminate etc…

I can’t be advising on what to use when I’ve not done a site survey myself.

 

[tvrulesme]

You’re lucky that you’ve found a sparky that’s willing to let you carry out all the design considerations.

Very lucky.

The key thing here is that he has specified the mm2 sizing of the cable and agreed that I will do the run which means he can just come in to do the connections and testing without worrying about drilling through my walls.

All parts of the cable are visible for him to inspect so if I chose to ignore his advice and run a thinner cable he would simply refuse to sign off or charge me to run the correct size cabling.

I'm not asking for someone to put their name to the design of this, just on whether with past experience EV Ultra it gives anything that seperate data and power cables would not.

 

[Electro-tech]

Quoted from Doncaster cables.
'' Voltage Band II is defined as all voltages which are used in electrical installations not included in Band I. This means that all 230V supplies are included in Band II.
Proximity of electrical services (extract from 528.1) - Except where one of the following methods is adopted, neither a Band I nor a Band II circuit shall be contained in the same wiring system as a circuit of nominal voltage exceeding that of low voltage, and a Band I circuit shall not be contained in the same wiring system as a Band II circuit. (i) - Every cable or conductor is insulated for the highest voltage present.

EV-Ultra® consists of power conductors and data cables that are rated to the same nominal voltage - therefore segregation of power and data is not required. ''

So I would have thought this means that if separate unscreened cables are run you will need to segregate them by 200mm.

 

[tvrulesme]

Quoted from Doncaster cables.
'' Voltage Band II is defined as all voltages which are used in electrical installations not included in Band I. This means that all 230V supplies are included in Band II.
Proximity of electrical services (extract from 528.1) - Except where one of the following methods is adopted, neither a Band I nor a Band II circuit shall be contained in the same wiring system as a circuit of nominal voltage exceeding that of low voltage, and a Band I circuit shall not be contained in the same wiring system as a Band II circuit. (i) - Every cable or conductor is insulated for the highest voltage present.

EV-Ultra® consists of power conductors and data cables that are rated to the same nominal voltage - therefore segregation of power and data is not required. ''

So I would have thought this means that if separate unscreened cables are run you will need to segregate them by 200mm.

Gold dust. Thank you so much. So this is the exact reason to spend the extra £££

 

[davesparks]

Quoted from Doncaster cables.
'' Voltage Band II is defined as all voltages which are used in electrical installations not included in Band I. This means that all 230V supplies are included in Band II.
Proximity of electrical services (extract from 528.1) - Except where one of the following methods is adopted, neither a Band I nor a Band II circuit shall be contained in the same wiring system as a circuit of nominal voltage exceeding that of low voltage, and a Band I circuit shall not be contained in the same wiring system as a Band II circuit. (i) - Every cable or conductor is insulated for the highest voltage present.

EV-Ultra® consists of power conductors and data cables that are rated to the same nominal voltage - therefore segregation of power and data is not required. ''

So I would have thought this means that if separate unscreened cables are run you will need to segregate them by 200mm.

There's nothing in that quote to prevent a cat6 cable being clipped next to an SWA cable.

The key point is that voltage bands should not be mixed within the same wiring system, so they cannot be in the same containment. Clipped direct insulated and sheathed cables are effectively a wiring system within themselves and so can be put next to each other without issue.

 

[davesparks]

Gold dust. Thank you so much. So this is the exact reason to spend the extra £££

There's no reason there to spend the extra.

The advantages of a combined cable are neatness and speed of installation.