EV charger installation

[tony9i9i9i]

I have a client who wants an EV charger installed, charger TBC, but about 7KW, installed about 20m away from this installation.

I've not done one before, but I understand I need to split the tails and main earth and add blocks so I can add an EV CU.

CU is in a cupboard and the tails and earth must be coming up from below it, would you look to add the blocks/EV CU in the meter cabinet or near the current CU? (put a bit of ply on the wall to mount on?)

I'd appreciate any advice or guidance, and if anyone can explain what the PEN issue is and what I need to do/look out for when selecting materials.

 

[buzzlightyear]

I have a client who wants an EV charger installed, charger TBC, but about 7KW, installed about 20m away from this installation

start in the beginning 20m to where. and what about the charger has it a built in rcd.and how you going to install the cable ect ect.

 

[tony9i9i9i]

start in the beginning 20m to where. and what about the charger has it a built in rcd.and how you going to install the cable ect ect.

Hi Buzz, thanks for responding, the client shortlisted 4, although he did say he wanted an untethered one. So on the basis that Zappie V2.1 7kW (ZAPPI-2H07UB-G) ticks all the boxes, I'd say that one.
It has pen fault protection and "Socket Protection" includes - "Overload, DC Sensitive and Fault Current Protected" so yes rcd.
Supply is in the house, and the charger is to go on the outside of the garage wall, so the run will be part clipped direct, and part buried underground.

 

[buzzlightyear]

Read the attached file first and work out how you are going to install it simples .

 

[timhoward]

I've not done one before, but I understand I need to split the tails and main earth and add blocks so I can add an EV CU.

Not necessarily. See below.

You need to check whether it is looped supply. If so, stop, and apply to connect.
You need to know existing max demand. If the house routinely pulls more than 60 amps (and it has an 80 or 100 amp service fuse) then stop, and apply to connect..
Otherwise you can crack on and install a charger that will throttle the charger if the grid limit exceeds 60 amps, and then tell the DNO you've done it.

Choosing a charge point that has built in double pole RCD protection including 6ma DC leakage protection makes this simple as at the CU it can just be an MCB in an existing consumer unit and armoured cable (so impact protection rules are met).

You'll need a CT clamp around the meter tails, so will need data cable to the charger too, or use one of the products such as EV ultra that has data within it.

Assuming it's TNCS earthing, you basically have a choice between isolating the earth at the charger and sticking an earth rod in, or connecting the CPC as usual and using a charger with PEN fault protection.

I'd appreciate any advice or guidance, and if anyone can explain what the PEN issue is

A PEN fault is when the combined Neutral and Earth supply conductor get's broken. This can create a very dangerous condition where all metalwork becomes live, and a person completes the circuit to earth. It's generally not so serious inside a house (vast simplification) but as cars live outside, it would obviously be pretty lethal to have a car body at a potential of 230v. Hence the PEN fault protection issue.

I've not done many of them myself but believe the above summarises most of the pertinent points.

 

[loz2754]

There's quite a bit more to installing an EV charge point than meets the eye. That's why there's a whole section in the regs and also a code of practice that should be followed. I would strongly recommend you get hold of a copy and study it before attempting to install one.

 

[timhoward]

That's why there's a whole section in the regs and also a code of practice that should be followed.

I admit I don't have the code of good practise. £73 is a bit above my impulse purchase threshold.
Would you say it's a practical and sensible document?

The reason I ask is that I reckon the 4 pages of regs and 2 pages of appendices are among the harder pages in the book to turn into practical reality as there seem to be several wild-goose-chase pathways that are unlikely to ever work in practise.

e.g. In my opinion, TN Indent ii is a waste of space. Single phase with 40 amp max demand you end up needing an additional rod with Ra under 2.5 ohms (and it only gets lower as the demand goes up), and the three phase calcs happily come out with a negative Ra to beat. (The original 18th edition 3 phase logic worked, but they messed up the logic in amendment 2 which stops you using the formula with smaller neutral currents.)
I doubt anyone can be making use of this clause. It's much simpler to TT the charge point or use PEN protection methods instead.

But my main question, is the code of practise helpful and worth having?

 

[loz2754]

Certainly worth it. It goes into great detail as to all the different charging modes, connection types etc.
Then there's a summary of the legislation relating to charging equipment.
There are risk assessment templates to follow with regard to choice of earthing arrangements.
Practical diagrams as to location of charging equipment relative to parking spaces.
Recommendations for protection against vehicle impact.
Accessibility and part M.
Clear diagrams explaining things like touch current.
Full explanations of the various methods of PEN fault protection.
Appendix on installation of earth electrodes.
Detailed instructions on inspection and testing.
On street installations. Commercial installations.
Vehicle as storage.
How and when to notify DNO.
Checklists for the different types of installations (dwellings etc.).
Explanation of the consequences of not providing adequate separation between PME and TT earthing systems below ground.
And lots more ...

Regarding your query

TN Indent ii is a waste of space

The code of practice states that achieving a suitably low value is generally not practicable.

PS.
The code of practice was recently updated to version 5, consisting of 208 pages with many diagrams and charts.

 

[timhoward]

Certainly worth it.

Thank you. Ordered!

 

[buzzlightyear]

The code of practice was recently updated to version 5, consisting of 208 pages with many diagrams and charts.

Are saying car charging practice up dated 5. Cost about £85.00 quid on IET
Webb page.

 

[loz2754]

Are saying car charging practice up dated 5. Cost about £85.00 quid on IET
Webb page.

Yes

 

[tony9i9i9i]

One last question, when working out the load on the installation and adding the EV Charger, can you apply diversity to the charger?

 

[buzzlightyear]

No you don't need to it's like having a 7kw shower. Is the ev charger add load to a consumer unit or separately.if you have a 60-80amp fuse it need up guarding to 100amp.

 

[tony9i9i9i]

No you don't need to it's like having a 7kw shower. Is the ev charger add load to a consumer unit or separately.if you have a 60-80amp fuse it need up guarding to 100amp.

I've done a bit more research. It's a 100 Amp Supply, split consumer unit with AC RCD on both sides. So will install a separate CU with double pole Type A RCD and surge protector to feed Wallbox Pulsar Max which has the RDC-DD and PEN fault detection built in.

 

[buzzlightyear]

[GALLERY=media, 29034][/GALLERY]




Watch.

(Edit: I've added the video to our website, and then used the embed feature on the media item to add it to the thread - Trying to make it even easier too... baby steps. Dan)