The single phase unit I fitted at a school had a local earth rod. I still had to export the house earth to protect the cable and isolate it inside the charger.
The neutral I believe had two purposes. One is to allow you to charge a non three phase EV and the other is to provide 230V for the control gear/interface on the charger.
you don't need a neutral with 3 ph surely?
But you might have to buy a minimum amount, like 25 metres
Does that mean you connected the SWA braid to the house earth (which seems to make sense) ?. If so, what is the earth connector in the cable connected to ?.
Not according to this guy, bear in mind he was sponsored by the manufacturer for this video. Interesting all the same.
I think it depends on what you have connected to it. The second hand 1HP three phase motor I obtained turned out only to have star wired connections so I did need a neutral. In another post someone pointed out that if you need to use a single phase for control circuits you also need neutral.
Zappis do not require an earth rod.
Yes, SWA braid connected up at head end and at the charger end it went into SWA gland inside a plastic box and no further. The charger had a local earth rod.
Then it makes no sense to use three phase wiring colours.
Would you have needed to export the earth if not using SWA - eg where the cable ran inside a house, under the floor? (Purely academic question for me in a terraced house with no off-street parking. Unless they allow consumers to be inventive - eg a swing arm derrick across the pavement.)
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It depends on your EVSE, but the new fancypants ones don't need an earth rod because they detect a current flowing from neutral to earth (in the case of a broken PEN) and disconnect the supply. In that case the EVSE does need a an earth from the supply to be able to detect that condition.
That is a good question as any short (lets assume you ran 4 core NYY-J cable) would be LL or LN and thus trip the head end MCB. A totally different thing to me using SWA.
I'll have to ask my contracts manager that one.
I suspect that you might not need to export and then isolate an earth. After all if the car charging point was at the other side of the wall to the CU I would not bother.
Roger Hayter snipped-for-privacy@hayter.org wrote in news: snipped-for-privacy@mid.individual.net:
No need for a neutral in that config, the phase currents cancel at the star giving no neutral shift.
All the examples I've seen have exported an earth on the armour of the SWA, but then isolated it within the EV charger, so it's only there to protect the cable, then use a rod to provide separate earth to the car.
It gets more involved if there's e.g. a bonded outside tap within reach of the car, as they you could touch two different earths.
The zappi route is more expensive, but easier as it disconnects all connections live/neutral/earth to the car if it senses a fault.
It's not just zappi now, there are others now which use the same method for PEN fault detection ...
Well you cannot just use 3 browns can you?
The vast majority of domestic chargers will be single phase 7kW chargers. There?s really no need for most folk to have three phase if they can charge overnight and the cost of upgrading a domestic supply to 3 phase just doesn?t make it cost effective. Pointless unless you have a very specific reason to need faster charging at home.
Tim
The box is this one:
That can be single or 3-phase. This is a new estate still being built. The house in question was built three or four years ago, so could well have a 3-phase supply.
This looks handy - provides the neutral/earth current detection and disconnect for an existing charger:
There's more call for it if you have multiple EVs that you might want to charge concurrently. For example families where the parents have two cars and maybe the offspring living at home have a car or two. Or households of multiple adults living in one house.
Theo
Is it 3 times, or is it sqrt(3) times ?
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