Installing a Tesla Wall Connector Chargepoint in the UK - with SFX!
Tesla have their own 'approved installers' for this kind of shebang, but they don't insist upon you using such. It's not a DIY job though; it has to be on it's own dedicated circuit with the right kind of overcurrent and shock protection, and the earthing and demand considerations need to be... well... considered. This sort of job requires certification, notification to Local Authority Building Control and notifiation to the District Network Operator.
Chargepoint earthing is a tricky issue at the best of times, and this was an unusual job where I was trying to comply with the regs, the CoP and the manufacturers' (sparse) instructions as well as the homeowner's expectations which made it challenging and meant that whichever way I did it could be viewed as questionable. It is possible to connect the rod back to the MET, but there are implications with doing that and keeping the touch voltage down which, in practice, means you need a ridiculously low Ra. We chose to TT the chargepoint and keep it isolated from the installation earthing which should be okay as it isn't possible to be in simultaneous contact with the vehicle and any point connected or bonded to the PME earthing at this site.
The RCD and MCB in the Lewden board look physically different as they're manufactured for Lewden's 'Control Gear' range (sometimes rebranded as store-own such as Denmans Curve). Lewden tech support confirmed it is just a rebadge and that Control Gear products can go into their enclosures. So why didn't I use the Lewden RCD shown towards the end of this video? Well, that snippet was filmed on a later date after I sourced the Lewden branded unit just to show for comparison in this video. That's how much I care about you, my beloved fucking audience.
I don't know how I didn't spot the 6mm cable coming from the tails when we were originally on site a few weeks ago; I must be going wire-blind. That fire suppression board is now powered from new 25mm tails from the Henley blocks which also serve DB1 and my Lewden board. Overkill? Sure. But I don't like the idea of thin wires one cannot isolate!
Dead testing of the SWA wasn't recorded on camera unfortunately, but was undertaken. The exterior Wiska box contains an earth block with the 2.5mm SWA CPC cores connected, a link wire for the SWA sheaths, the 6mm wire to the charger and a 16mm wire to the rod.
The black cores used as CPC within the SWA's could have been employed to increase the overall CSA to 7.5mm square for line/neutral with the armour used as the earthing for the SWA cable to allow full 32A operation, but there is regulation 434.4 to consider which permits conductors in parallel to be overcurrent protected from the load end as we've done here, but does go on to say "for more than two conductors in parallel, a fault current protective device shall be provided at the supply and load ends of each parallel conductor", so breaking into the extra core to deliver higher current would have potentially made things more complicated. The armour itself has an equivalent CSA of 19mm squared for each cable so would have sufficed as earthing; it wasn't necessary to have dedicated earth cores, especially as they don't go anywhere in this case. Still, current limiting the bugger is better for the DNO paperwork.
The only way to get the Zs from the Wall Connector was with it powered up with the front cover removed. It's own internal protection prevented any Zs testing from the charge socket which is annoying as that's the kind of thing we use the (expensive) ChargeCheck unit for, and that damn thing doesn't see much action to justify its existence!
This job was more awkward than expected, and took a few additional hours thanks to issues such as the main tails not being where we expected them.
Regarding (ongoing) argument over RCD type, Tesla's UK page says the following: "The Tesla Wall Connector does not measure DC current leaking, so an RCD Type B or a specific Type A-EV needs to be installed." I have to say, I missed the "EV" bit, so this may be the wrong RCD for the job. If undertaking the same, source a B or an A-EV to comply.
www.tesla.com/en_GB/support/h...
Related videos:
My surge protection video where I got the tail length wrong: • Exciting new SPD insta...
My follow-up video on surge protection: • Surge protection - a c...
Previous video shot on this site: • On the job with THE Sa...
John Ward's video on EV charging earthing: • BS7671 Section 722 Ele...
John Ward's farmyard artistry: • Earth Electrodes Part 1
Artisan Electric's advice on becoming OLEV accredited for EV chargepoint installations: • How To Become an "OLEV...
e5 Group's video on DC affect on Type-AC RCD's: • Effect of DC on AC RCD...
If Hollywood is watching, I am available for providing top special effects in future blockbusters. 50% cash up-front. Cheers!
14 окт 2019
