But you wouldn't connect the neutral to either the ground rod or the earth terminal of the charger.
Car Chargers Chargers
- Thread starter RyanM
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Correct. the earth for the charger should not be connected to the earth of the house if ground rod is used to earth the charger.
Incoming Neutral is from where the PME "earth" for the house is created. So in fact the CPC is not true Ground but is in reality Neutral. This is safe for every one inside the equipotential zone inside the house provided no extranious potentials cross the boundary of the zone. But if you export the earth to something that is outside the zone and has a connection to true ground then ground current will flow.
Never mind where the earth(s) is/are connected.
You posted a diagram to illustrate a problem and it showed the N connected to an earth rod and the earth teminal of the charger. Which is not a connection anybody would make.
But they would ( non intentionally maybe ) if they "earthed" the SWA at the house and connected it to the metal work of the charger when the charger had a ground rod.
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Why would anyone do that?
Hi Guys,
Thanks for all the replies.
For my own knowledge and learning, where would I find this in the 17th Edt book please?
Thanks a lot
Thanks for all the replies.
For my own knowledge and learning, where would I find this in the 17th Edt book please?
Thanks a lot
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Not sure what is in amendment 3 the original section 717 fig 717.3 and 717.4 show it with and without isolation transformer. However the IET has published a book specially on the supply to electric vehicles.
The problem is the same as with caravans at home. In the caravan park fire regulations means the caravan is some distance from any building, so using a TT system is no problem, only TT or TN-S is allowed. But in the home the caravan may be parked close to the building, where mine is parked one can touch both the gas and electric meters and the caravan at the same time. In your case 2 meters is rather close and the voltage gradient under fault conditions can be very high.
There is nothing to stop having an earth rod (although it would not be called an earth rod) and a DNO earth, but it depends how good the earth rods are? Again under fault conditions very high currents can run, and there is no fuse to protect.
What is done in some cases is to put a huge resistor between the two earths to limit the current that can flow. Seen this with a gas terminal. But that is unlikely to be the case with your system.
As with caravans the rules for caravan sites do not stretch to the home. So with electric cars what can be installed at home is not the same as what can be installed in a public charging point.
All you can do is buy the book and follow what it says. see this http://www.theiet.org/resources/standards/ev-charging-cop.cfm and also wiring matters here http://electrical.theiet.org/wiring-matters/57/ev-cop/index.cfm it is complex, there is no simple answer.
As to showing the installers got it wrong, that is not easy, the BS7671 is not law, when I contracted work out I would write into the contract that BS7671 was to be followed unless written consent was given to deviate from it. I also say safety devices should be at least as good as the original. In the main this allowed me to withhold payment if the job was wrong. But unless a contractor is requested to fit x number of charging points complying with the IET Code of Practice for the Installation of Electric Vehicle Charging Equipment then it's hard to show he did not do as asked. And we are at least up to amendment 2.
The problem is the same as with caravans at home. In the caravan park fire regulations means the caravan is some distance from any building, so using a TT system is no problem, only TT or TN-S is allowed. But in the home the caravan may be parked close to the building, where mine is parked one can touch both the gas and electric meters and the caravan at the same time. In your case 2 meters is rather close and the voltage gradient under fault conditions can be very high.
There is nothing to stop having an earth rod (although it would not be called an earth rod) and a DNO earth, but it depends how good the earth rods are? Again under fault conditions very high currents can run, and there is no fuse to protect.
What is done in some cases is to put a huge resistor between the two earths to limit the current that can flow. Seen this with a gas terminal. But that is unlikely to be the case with your system.
As with caravans the rules for caravan sites do not stretch to the home. So with electric cars what can be installed at home is not the same as what can be installed in a public charging point.
All you can do is buy the book and follow what it says. see this http://www.theiet.org/resources/standards/ev-charging-cop.cfm and also wiring matters here http://electrical.theiet.org/wiring-matters/57/ev-cop/index.cfm it is complex, there is no simple answer.
As to showing the installers got it wrong, that is not easy, the BS7671 is not law, when I contracted work out I would write into the contract that BS7671 was to be followed unless written consent was given to deviate from it. I also say safety devices should be at least as good as the original. In the main this allowed me to withhold payment if the job was wrong. But unless a contractor is requested to fit x number of charging points complying with the IET Code of Practice for the Installation of Electric Vehicle Charging Equipment then it's hard to show he did not do as asked. And we are at least up to amendment 2.
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