Regulation 411.3.1.1

Question

Hi Guys, 
 Hopefully a simple one to answer. 
 Can 'the same earthing system' described in Regulation 411.3.1.1 be satisfied if both supplies originate from the same DNO PME cable in the street, for example where 2 neighbours are both charging their EV's on the drives which are side by side or a drive is next to a metal lamp post already installed on the street? 
 Regards 
 Mark

AJJewsbury · Accepted Answer

As the lamp post are going to be located next to the parking bays, adopting a TT earthing system for the chargers is not really an option. 
 
 Probably worth talking to the particular DNO in question - it's been reported that some aren't entirely convinced by open-PEN devices and will often refuse to supply a PME earthing terminal for on-street type charging installations. Their preferred solution would then to TT the charge points - together with anything else that's within reach (e.g. lamp posts). (I guess you could have a common TT earthing system even if the metering was split). 
 - Andy.

gkenyon · Answer

Mark Fleming said: So where we might have an on street installation and the DNO have confirmed we could have a PME supply to the feeder pillar, along side an O-Pen device complying with 722.411.4.1 (iv) and the supply is from the same DNO cable in the street as the lamp post, do we still need to treat them as a sperate earthing systems and keep them apart as with a TT and PME? 
 No that example is NOT a separate earthing system. 
 Mark Fleming said: and keep them apart as with a TT and PME 
 The requirements of Regulation 411.3.1.1 regards simultaneously-accessible exposed-conductive-parts applies whatever the earthing arrangements wherever ADS is used. Therefore, would also apply if you had an existing building supply, powering lights in the car park, and you bring in a new supply for the EV charging points - the charging points and lights would have to be on the same earthing system. 
 How you might achieve that depends on a lot of different factors.

Regulation 411.3.1.1

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