[Citizen38]

Hi, I'm in the process of installing a Project EV 7KW unit and just checking the unit find there is no continuity between the Protective Earth and the metal chassis of the unit.
This seems pretty irregular, is there a special case for this on EV chargers?
Thanks

 

[freddym]

Hi, I'm in the process of installing a Project EV 7KW unit and just checking the unit find there is no continuity between the Protective Earth and the metal chassis of the unit.
This seems pretty irregular, is there a special case for this on EV chargers?
Thanks

Hi, what does the installation instructions have to say. It could be that the unit is designed and certified as reinforced insulation in which case you would NOT want to earth the casing. Ultimately you will need to be guided by what the manufacturer have to say.

 

[HandyAndy]

This may be quite deliberate. There's been a lot of chat about these sorts of thing here:
Time for metal chargers?
I'm not a sparky, so take what I say with a pinch of salt! It seems there's a possibility that the EV could go faulty, and the bodyshell of the car goes live, which could push current back up the PE line back into the EVSE (Newer regs & EVSEs have PEN-loss detection & additional PE contact breaker to isolate the car in it's entirety if this happens, but older EVSEs lack this feature). And at the same time, the house's PE line could develop a fault where it's no longer connected back to the grid/substation, so this combo could make anything connected to PE become dangerous. Your car located outside is not regarded as being part of the house, so needs separate Earthing, or extreme caution/special safety detection as I see it.

Maybe this is why the metal case is not connected to the House PE, but instead should (maybe?) be connected to it's own Earth Rod? If I understand what the sparkies say, the house's PE (should connect back to grid/substation) should not at the same time connect to your Earth Rod; if it did, your earth Rod could end up becoming the "safe" route to Earth for the local houses, if the grid's PE line back to substation got broken some distance away. Something like that anyway!

 

[Citizen38]

Thanks for the replies chaps, I have contacted the supplier for info. The installation guide is completely useless for this unit, the vendor needs to completely re-write it in my opinion.
I'll update when I get the answer for future reference.

 

[freddym]

Thanks for the replies chaps, I have contacted the supplier for info. The installation guide is completely useless for this unit, the vendor needs to completely re-write it in my opinion.
I'll update when I get the answer for future reference.

On a practical front, look inside the metal casing and see if there is an earthing boss. Also check visually for any bolted earthing bonding. Then if you know what you are doing, mega the PE internal terminal to an unpainted section of the casing.
Next you want to think about wiring; if you are bringing in the supplylly lylylyly

 

[freddym]

If you are bringing in the supply via SWA cable that would normally also in itself earth the casing via gland and banjo/piranha unless you deliberately do otherwise....

 

[Citizen38]

If you are bringing in the supply via SWA cable that would normally also in itself earth the casing via gland and banjo/piranha unless you deliberately do otherwise....

Interestingly the case has plastic glands for the SWA and no explicit earthing connection internally, just the terminal block for the L/N/E conductors so I suspect this is a design decision to not have the casework connected to the protective earth.

 

[freddym]

Interestingly the case has plastic glands for the SWA and no explicit earthing connection internally, just the terminal block for the L/N/E conductors so I suspect this is a design decision to not have the casework connected to the protective earth.

It very much sounds like a reinforced insulation design : pity the GroWatt manufacturer dont make this clear. Normally you would also expect to see some internal insulation in key areas such as cable terminations, take a close look.

 

[HandyAndy]

BTW, someone mentioned in another thread that a metal case around an EVSE will probably screen any wifi/mobile-phone signals, if this project has such "smarts" in it.

 

[dk6780]

BTW, someone mentioned in another thread that a metal case around an EVSE will probably screen any wifi/mobile-phone signals, if this project has such "smarts" in it.

Good point - they do.

 

[Citizen38]

The supplier came back on this item describing the unit double insulated class 2, the casing is separated from the earth due to the fault potential from the vehicle.

 

[freddym]

The supplier came back on this item describing the unit double insulated class 2, the casing is separated from the earth due to the fault potential from the vehicle.

Great, shame on them for not having this noted on the datasheet and installation instructions.