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Electrical Vehicle Charging Points - True earth on solid floor

Apostolos
Good afternoon.

The problem with EVC Points in a few words is that it introduces the PME (the MET in reality) voltage on the metallic car body. Then, if someone touches the car (under PME voltage) and stands on the ground touching the TRUE EARTH potential he will be introduced to a high voltage in case of an open PEN incidence. 

There are some gross guidlines ( https://www.electricvehiclechargepoint.com/ev-resources/earthing )that say

-If the EVC is outside then TT is needed (the person touches the true earth)

-If the EVC is inside and no charging happens on the outside then PME can be used (the person does not touch the true earth)

Then my question is:
WHAT IS THE POTENTIAL OF A CONRETE FLOOR IF THE EVC POINT IS INSIDE THE BUILDING????

Why do we assume that the concrete floor inside the building is on PME potential and so the EVC can be on PME?

If it is a metal building then I can see somehow that the concrete floor is in touch with the metal skeleton which is bonded to the MET so the concrete floor could be assumed to be on PME potential (correct me please if I am wrong)

If the building is concrete, how on earth this solid concrete floor is considered to be at PME potential????

 


Parents
  • 0
    The broken PME will bring any metal casing connected to the MET through the CPC to 230V.

    So forget for now the EVC in the basement car park.

    Lets focus for a moment on the metal casing of a grill oven in the kitchen which is also at 230V under a brokent PME.

    Someone touches the casing and stands on the floor in the kitchen.

    Will he get a shock?

    My logic says he will. However this implies obviously that the kitchen's floor is at 0V and not....PME earth i.e. 230V.

    How is this different than the car park's floor while we are touching the metallic car body?

    I have never heard anyone asking for a TT system for the....kitchen!

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  • 0
    The broken PME will bring any metal casing connected to the MET through the CPC to 230V.

    So forget for now the EVC in the basement car park.

    Lets focus for a moment on the metal casing of a grill oven in the kitchen which is also at 230V under a brokent PME.

    Someone touches the casing and stands on the floor in the kitchen.

    Will he get a shock?

    My logic says he will. However this implies obviously that the kitchen's floor is at 0V and not....PME earth i.e. 230V.

    How is this different than the car park's floor while we are touching the metallic car body?

    I have never heard anyone asking for a TT system for the....kitchen!

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