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Topic Title: Vehicle Charging Point and
Topic Summary: TT earthing.
Created On: 23 June 2015 09:21 AM
Status: Read Only
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 23 June 2015 09:21 AM
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Joined: 20 February 2014

Is 722.411.4.1 (iii) asking for a voltage operated earth leakage circuit breaker to be installed (or modern equivalent)? Are they being reintroduced in one form or another?


 23 June 2015 10:00 AM
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Joined: 18 March 2015

The thing being proposed is slightly different, since it has to disconnect not only the supply but the CPC also (since the problem it's trying to solve is open-circuit neutral in a PME supply, with the car tending to bridge between outdoor true earth and places such as a garage that are supposed to be within an equipotential zone).

So far as I know, none are yet available; current practice is to TT supplies to outdoor charging equipment.

The problem case is a chargepoint installed just inside the door of a garage connected to a house. The cable will obviously reach to a car parked outside, so you'd want to TT the supply so as to avoid the car's bodywork being live with respect to true earth, but equally the car will usually be parked inside the garage and there might be other appliances (washing machine?) in there connected to the PME earth, so having the car earthed to true earth makes things worse.

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