have been on a course today funnily enough, run by ev-box im approved to install rolec and they are not great quality, the bits inside are made by chint! enough said. rolec themselves dont devlop the tech side and buy off the shelf and sell cheap to flood the market, have installed some rolec units and am not impressed at all.
The ev box stuff is much much better, yes it can be around ÂŁ200 more expensive but it is far superior in quality. Also they have better support than rolec, i will be doing just ev-bov from now on in, i will push them over rolec anyday. i found the rolec uk support quite poor,
I can give you the info for the uk contact guy if you want it? also if you fancy a free days training and free buffet lunch then ev-box are your people.
In terms of earth, if you are 100% sure its tns and not pme at any point back to dno transformer then can use dno's earth. if pme then you can export it to a shed or garage if no extraneous metal parts etc and the car will remain in the garage during charging.
Otherwise whack a rod in, it saves any ambiguity, you may have to put 2 in 3m apart if you cant get the reading. you can utilise the single or dual rods for all chargers. for what you want i would go for the business designed units rather than the rolec ones,
Its all good and well saying a fast charge but if the car is sat at work for 6 hours, why rush the charge? it can charge over the 6 hours as if its done after 2 hours it doesnt achieve anything other than more cost for a higher rated unit. unless there is a time requirement to charge it in say 2 hours, the slightly lower rated charger will achieve the same. if you had a fast charge unit that can charge a car in 2 hours, then why have 3? as it only takes somebody to move to allow the other 2 cars to charge up...
the ev-box people do better units having seen them first hand today.