EV charger issue - Garo PME trips

[ElectricallyRandom]

https://www.digikey.be/htmldatasheets/production/2996418/0/0/1/dua55-datasheet.html

ElectricallyRandom - Please would you look at the section 'Range Settings' in the link above and tell me what voltage window and measuring range have been selected by the four little switches on the voltage monitoring relay behind the flap.

Apologies for a late answer - busy time. I've just checked and here's the settings. That should mean 230V +-10% according to the datasheet. What do I make of it... ?

 

[marconi]

Apologies for a late answer - busy time. I've just checked and here's the settings. That should mean 230V +-10% according to the datasheet. What do I make of it... ?

We will move on to this aspect after trying a lower maximum charging current.

 

[HappyHippyDad]

If the car is inside the garage there is no need for PEN fault protection. (From the Code of Practice)

I don't think its quite as simple as that. I think it's more along the lines of if the vehicle cannot be charged outside then there is no need for PEN fault protection (on PME or TNS system (as you have to assume TNS is actually PME and not a proper TNS) ). If the EVCP is installed in the garage and the car could still easily be charged outside due to the position of the charger then you still need PEN fault protection.

 

[loz2754]

I don't think its quite as simple as that. I think it's more along the lines of if the vehicle cannot be charged outside then there is no need for PEN fault protection (on PME or TNS system (as you have to assume TNS is actually PME and not a proper TNS) ). If the EVCP is installed in the garage and the car could still easily be charged outside due to the position of the charger then you still need PEN fault protection.

Indeed. You worded it in a less ambiguous way.

 

[ElectricallyRandom]

We will move on to this aspect after trying a lower maximum charging current.

Charged at 26A instead of 32A tonight - went without the Garo tripping. Will try a few more times, see how it goes.

 

[marconi]

For your interest, the heating effect of a 26A current is 66% of the heating effect of a 32A current since the heating effect of a current is proportional to the square of the current. So {26/32}exp2 = 0.66 x 100 = 66%

The RCBO contains an electro-thermal-mechanical trip which uses the current flowing to perform its overcurrent detection function.

 

[marconi]

ElectricallyRandom: Where are we going? If we find that the RCBO holds with a charging current of 26A then there is some evidence that a factor in the problem is the magnitude of the current and its heating effect. I suspect - don't know for certain - but either the RCBO is faulty as others' experience has suggested - in which case it is a simple one for one replacement, or that even with a new RCBO in place the real problem is that for the high long term charging current of 32A, the operating current of the RCBO is derated to a lower value than its marked 40A and less than 32A. If this is indeed the case what I would try next is to re-arrange the voltage relay, contactor and RCBO on the rail of the GARO box so that from left to right we had RCBO-Voltage Relay - Contactor. By doing this we move the warm coil of the contactor away from the warm electro-thermal-mechanical trip mechanism of the RCBO and thereby allow the RCBO to operate at a lower temperature which in turn reduces the amount of derating. We can then trial a charging current of 32A again. Does this seem like a plan if we find that at 26A the RCBO holds closed? You will have to call back the electrician to do the re-arrangement. It would be no more than an hour of his time.

I still think the 4mm2 cabling is too thin because the voltage drops as measured by the Tesla charger point are in my view excessive and power is being wasted warming them up. Typically 6mm2 would be used. But a simple solution is to double up the 4mm2 cabling.

 

[miladenaa]

I can understand not wanting to knock in a meter of earth rod, but to detect loss of PEN it really only needs to be 6 inches. However

 

[marconi]

ElectricallyRandom: ?????????? Did I contribute as others have in vain?

 

[ElectricallyRandom]

ElectricallyRandom: ?????????? Did I contribute as others have in vain?

Oh yes you have I have dropped the current to 26A and last night on 3rd charge at lower current my pen device has tripped again. Just lowered the current down to 22A, but this is clearly not sustainable. I totally take your point on reshuffling the pen fault device's modules to help with heat, but it feels like a bit of hit and miss. I am very tempted to swap it altogether (would gladly just remove it tbh, but that's not quite right).