An engineer friend recently recieved a request to look into the possibility of designing the installation for EV Charging points located on the top floor of a multi storey car park. The building is PME but begs the question of how can the EV Chargers be TT'd correctly ? IMO I would recommended chargers be installed on the ground floor if not only for ease of access (with the possibility of a disabled EV driver indiscrimanately having to park on the top floor) but also the TT spike installation would prove very difficult to install. My advice to him was to rethink the location but again wondered if anyone else had encountered this and how they approached the problem ?
Won't the steel barriers to protect this occurrence be connected to some steelwork that is buried in the ground?
Assuming you mean prevent, rather than protect, any guard rails and fencing will only be driven into terra-firma one imagines on the bottom level. Any such barriers on the upper floors will presumably be bolted to tags cast into the concrete floor slabs. And if by some happenstance the whole thing is one big electrode, perhaps a steel walled and floored car park, rather than concrete, then well you have your electrode upstairs anyway.
In all cases, to minimise the shock risk, you need to bond the charger CPC and so the car metalworks to the same 'earth' as the accessible metalwork on that floor, if it is at a true terra-firma potential or not.
Won't the steel barriers to protect this occurrence be connected to some steelwork that is buried in the ground?
Assuming you mean prevent, rather than protect, any guard rails and fencing will only be driven into terra-firma one imagines on the bottom level. Any such barriers on the upper floors will presumably be bolted to tags cast into the concrete floor slabs. And if by some happenstance the whole thing is one big electrode, perhaps a steel walled and floored car park, rather than concrete, then well you have your electrode upstairs anyway.
In all cases, to minimise the shock risk, you need to bond the charger CPC and so the car metalworks to the same 'earth' as the accessible metalwork on that floor, if it is at a true terra-firma potential or not.
