Recently sat the 18th Edition Course and of the understanding EV Charging points shall be fed from a TT Supply. PME is acceptable only when feeding any other equipment ie Lamp posts Ticket Machines for example and providing Type A or Type B RCD is fitted and the Charger point is then to be separately spiked. Just looking on the attached and a company called Pod Point suggest TN-S is acceptable with no need for an earth spike. Wondered if anyone else has come across this diagram and can confirm TN-S is acceptable without the spike (see - page 2)
There are, however, a number of serious safety concerns with making a separate TT earthing system for the charge points, not least:
there must be no possibilityof simultaneous contact between the vehicles on charge, and exposed- or extraneous-conductive-parts in the original installation (this is a basic requirement of BS 7671).
there must also be separation underground, between the earth electrode(s) for the charge points, and any buried metalwork and exposed conductive parts connected to the PME earthing terminal. Some DNOs have minimum separation requirements of as much as 3.6 m. I would also be wary about the earthing arrangements for the HV transfromer.
An alternative is to use an isolating transformer for each charge point, but this comes with a cost.
To complete this installation safely, sounds like it's not an east one. It's definitely worth getting a handle on the earthing arrangements ... as has been said, working to the Code of Practice strongly recommended.
There are, however, a number of serious safety concerns with making a separate TT earthing system for the charge points, not least:
there must be no possibilityof simultaneous contact between the vehicles on charge, and exposed- or extraneous-conductive-parts in the original installation (this is a basic requirement of BS 7671).
there must also be separation underground, between the earth electrode(s) for the charge points, and any buried metalwork and exposed conductive parts connected to the PME earthing terminal. Some DNOs have minimum separation requirements of as much as 3.6 m. I would also be wary about the earthing arrangements for the HV transfromer.
An alternative is to use an isolating transformer for each charge point, but this comes with a cost.
To complete this installation safely, sounds like it's not an east one. It's definitely worth getting a handle on the earthing arrangements ... as has been said, working to the Code of Practice strongly recommended.
