Installing a 3 phase rapid EV charger?

[pc1966]

I don't think it will need it's own meter as this will be the owners tractor, I will ask him though as he has asked for meters before on other work around the place.

A 3 phase meter! More questions!

If needed then something like this should do and does not need a separate enclosure:

Electricity Billing Meters | CEF

I've just thought of a bit more in relation to cable size....

Lets say this is the 400V/32A charger.

1. Does each line conductor have to be able to cope with 32A?

Yes, if that is the spec.

Check the cable tables though as the rating for, say, 6mm, is different if single phase or three-phase as more I^2*R losses per bundle.

2. I realise we have been given 32A in this case, but if we just had the wattage of the charger (lets say 22kW), is the calculation the same as single phase. I.e 22000/400 = 55A?

No your equivalent is 22000 / (3 * 230) = 32A

If you imagine a star-connected load, then you can see that each L current with the L-N voltage gives you 1/3 of the total power.

The equivalent delta case (400V L-L) is more complicated as each L current is shared by two of the arms (say L1 has loads going to both L2 and L3), and not in-phase to make any calculation simple. Answer is 22000 / (sqrt(3) * 400) and is the "same" (though 400V L-L is not exactly the same as 230V L-N)

TL;DR: So just work with the star model as it gives the same answer!

 

[pc1966]

the actual circuit is standard 3 phase from what i can see, not sure if it needs PEN fault or Type A rcd etc as its not a standard ev charger within the code of practice etc.

Good point as it looks TN-C-S supply.

 

[Risteard]

Something worth considering with three-phase charge points is that the phase sequence should actually be varied between units. So if there is a charge point connected L1-L2-L3 then an additional unit should be L2-L3-L1 or L3-L1-L2. This is to prevent them all pulling off the same phase where the vehicle is only capable of single phase charging. Obviously maintain the phase rotation though.

 

[HappyHippyDad]

the actual circuit is standard 3 phase from what i can see, not sure if it needs PEN fault or Type A rcd etc as its not a standard ev charger within the code of practice etc.

I'll try and find some specs for the unit, but something like this may be suitable?

3 Phase EV Connection Unit with 4 Pole 32A Type A RCBO

Built-in matt:e O-PEN technology, which allows for the connection of 1 x 32A three phase load to the existing PME earthing facility

www.cef.co.uk

Is this the standard price for a 3 phase Matt e, expensive!

 

[Risteard]

I'll try and find some specs for the unit, but something like this may be suitable?

3 Phase EV Connection Unit with 4 Pole 32A Type A RCBO

Built-in matt:e O-PEN technology, which allows for the connection of 1 x 32A three phase load to the existing PME earthing facility

www.cef.co.uk

Is this the standard price for a 3 phase Matt e, expensive!

Yeah - CEF are actually one of the cheaper wholesalers for Matt:e O-PEN devices.

 

[HappyHippyDad]

Some more...

In the picture in the OP, you can see a separate small enclosure housing a 4 pole RCD (300mA). This feeds the 3 phase CU (and the agricultural single phase meters) where I will be taking power from. I'm guessing this will be a type AC RCD which is going to be a problem if I then need a Type A (or B) RCD downstream to this for the charger.

Am I going to have to change this RCD to the relevant type? They look like a ridiculous price!
Or, I could take the supply from the henley blocks to the left of the 300mA RCD which have no RCD protection? This seems better, as the cable from the Henly blocks to sub DB will not need RCD protection and I could locate it close to the henley blocks in the same room.

 

[Gavin John Hyde]

I'll try and find some specs for the unit, but something like this may be suitable?

3 Phase EV Connection Unit with 4 Pole 32A Type A RCBO

Built-in matt:e O-PEN technology, which allows for the connection of 1 x 32A three phase load to the existing PME earthing facility

www.cef.co.uk

Is this the standard price for a 3 phase Matt e, expensive!

Given the cost of the matt:e and it being a farm could you not get a rod in using some machinery?
Like wise if its being used solely inside then use the pme.

 

[HappyHippyDad]

Given the cost of the matt:e and it being a farm could you not get a rod in using some machinery?
Like wise if its being used solely inside then use the pme.

A rod may be the way forward as the tractor could be charged outside.

 

[westward10]

Im finding all those swirling conductors quite pleasing to the eye.

 

[Risteard]

Some more...

In the picture in the OP, you can see a separate small enclosure housing a 4 pole RCD (300mA). This feeds the 3 phase CU (and the agricultural single phase meters) where I will be taking power from. I'm guessing this will be a type AC RCD which is going to be a problem if I then need a Type A (or B) RCD downstream to this for the charger.

Am I going to have to change this RCD to the relevant type? They look like a ridiculous price!
Or, I could take the supply from the henley blocks to the left of the 300mA RCD which have no RCD protection? This seems better, as the cable from the Henly blocks to sub DB will not need RCD protection and I could locate it close to the henley blocks in the same room.

Yes the upstream device will need to be at a minimum Type A (assuming DC Leakage protection in the EVSE), otherwise Type B. Obviously also S-type (time delayed).

For example a number of EVSEs I installed for a well-known courier firm I replaced the upstream S-type RCCB for a Type A 300mA for the distribution circuit. This went to a switch fuse and then onto the DBs. I had triple pole circuit breakers in the DBs feeding four pole RCCBs. (It was a TT installation.)