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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

    It’s not unusual get an electric shock from a car with an internal combustion engine when you touch it due to static



    That certainly used to be the case - I remember many a static shock from the car door handle as a child.  I'm not sure it's as prevalent as it used to be though - I beleive that modern vehicle tyres are designed to be slightly conductive specifically to dissipate static.


    I'm not sure insulating footwear would help much with static shocks - a small current can flow from a charged body to an uncharged one even if it's not to earth.


      - Andy.
Reply
  • 0

    It’s not unusual get an electric shock from a car with an internal combustion engine when you touch it due to static



    That certainly used to be the case - I remember many a static shock from the car door handle as a child.  I'm not sure it's as prevalent as it used to be though - I beleive that modern vehicle tyres are designed to be slightly conductive specifically to dissipate static.


    I'm not sure insulating footwear would help much with static shocks - a small current can flow from a charged body to an uncharged one even if it's not to earth.


      - Andy.
Children
  • 0 in reply to AJJewsbury

    We used to have chains dangling from the rear bumper to discharge the static. 

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