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EV chargers in basement car parks - earthing

GHEC

I'm working on a project that will have a few 7kW single phase EV chargers fed from a three phase system.

The chargers will be located in the car park in the basement of the building. The chargers have built-in type B RCDs.

I was hoping someone might be able to provide some guidance in relation to the earthing arrangement. 

Strictly speaking, the chargers are "indoors" and within the equipotential zone. But since the installation is in the basement, would it be best to treat it as an outdoor installation and allow for installing separate earth rods? Or will this be problematic with any potential metalwork in the ground?

Parents
  • 0

    Mr Graham Kenyon is the expert in such matters so all I can do is say what I would do. I have a strong opinion that conversion to TT is a poor substitute to integral  open pen protection. Likely 722.411.4 indent (v) which for three phase is probably indent (iii) with a means of disconnecting the contactor when small values of current appear in the protective conductor to the car when someone touches the car on an open pen fault.

    We are currently installing 10 twin head units in an open car park and it pains me to convert to TT. The manufacturer is from a Nordic country, where, apparently, they don’t see the risk quite the same as we do.

Reply
  • 0

    Mr Graham Kenyon is the expert in such matters so all I can do is say what I would do. I have a strong opinion that conversion to TT is a poor substitute to integral  open pen protection. Likely 722.411.4 indent (v) which for three phase is probably indent (iii) with a means of disconnecting the contactor when small values of current appear in the protective conductor to the car when someone touches the car on an open pen fault.

    We are currently installing 10 twin head units in an open car park and it pains me to convert to TT. The manufacturer is from a Nordic country, where, apparently, they don’t see the risk quite the same as we do.

Children
  • 0 in reply to lyledunn

    Oh and by the way, no one installing chargers should be without a copy of the COP for Electric Vehicle Charging Installation and should be familiar with its contents.

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