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Posted By Topic: Ev Chargers

Sep 08 2017 08:43

Hi All

Apart from the info on the engerysafe website, is there anything else i can look at regarding charger installations? particularly public charging

Got a couple to install next week and want to make sure we get everything ok


Sep 08 2017 09:55

The manufacturers instructions and any additional information from the NZupplier.

Sep 08 2017 15:35

Nothing specific that I've seen, but in my case I installed a separate RCD just for the vehicle charger (peace of mind that the car will still charge overnight even if something else trips). There's also some logic to recommending running larger cable than the minimum for voltage drop as it will save some loss.

16A charger on 2.5mm is around 3.4W per meter where 6mm is 1.4W/m. Average EV spends around 400-600 hours charging a year.

Sep 08 2017 16:11

Thanks, we are doing a couple of Tesla Chargers. they have a fairly decent current draw depended on how fast you set the charge rate too

We are running 3phase 16mm for ours

Sep 08 2017 17:45

Ah, right. The Tesla wall chargers are a lot better than most, given the level of adjustability. Different kettle of fish in terms of power level, as well!

Sep 20 2017 20:32

Does anyone know the reason for Type B Rcds for Ev chargers, the ones for our job are about 500 from Schneider (4p)


Sep 20 2017 20:58

Will most likely be because of nuisance tripping you would get otherwise. I know of at least 1 brand of VFD that requires this. And yes until more widely used extremely expensive.

Sep 20 2017 22:08

the reason for type B RCD is because of the continuous and constant DC residual currebts in the supply connection if greater than 6 mA current TYPE B is required.

BTW the Worksafe guidelines for EV charges mandates the use of type B RCDs for large EV chargers due the DC rsidual current levels (pulstaing and constant) under earth fault conditions.

Sep 21 2017 07:52

Yer i thought the Dc factor was the reason
We had advice from the manufacturer of the charger that NZ work safe guideline were very extreme and that elsewhere in the world they all use type A RCDs

Sep 21 2017 09:02

WillJ Sep 21 2017 07:52
Your comment (part only)

We had advice from the manufacturer of the charger that NZ work safe guideline were very extreme and that elsewhere in the world they all use type A RCDs

My comment

That is incorrect, the WorkSafe NZ EV rules follow the international standard IEC 61851 series in the choice of RCD type.


Sep 21 2017 09:17

Just to be clear, it's not about "nuisance tripping", but instead it's about avoiding failure-to-trip under fault conditions.

Sep 21 2017 23:29

just out of curiosity, what legal standing to the Worksafe Guidelines carry? and will they eventually form part of a standard for ev charging?

Sep 22 2017 08:38

As far as I am aware the Worksafe guidelines are exactly that: guidelines; they are not cited by any legislation or Regulation - yet.

Coming edition of "3000" will have an Appendix providing further information, also some requirements for NZ residential installations. Sometime after publication this will be cited by ESRs - probably late next year.

I would expect the same ESRs amendment to also cite the Guidelines in some way. Meantime, doing anything contrary to the Guidelines may not be directly unlawful, but you might have to defend a more general charge of (for instance) not being electrically safe. It would be hard to mount such a defence.

Just like a "should" statement in a cited Standard; you could end up in front of a court - perhaps even a Coroner's court - and have to justify not following the readily available official advice.