Installing a 3 phase rapid EV charger?

[HappyHippyDad]

A bit of an embarrassing question.

I have a regular customer who I enjoy working for. He has asked me to install an EV rapid charger for his avant loader (electric tractor type thing). I always turn down 3 phase jobs as I don't feel I understand it fully, but I'd like to do this job.

I believe this is the charger (400V/32A version) Rapid battery charger, e6 - https://www.avanttecno.com/uk/options/rapid-battery-charger-e6

I have added a picture of the 3 phase supply.

1. Are there any additional tests to do, compared with single phase? Phase rotation etc.

2. Is it simply a matter of connecting L1, L2, L3 from the Henly blocks (or perhaps the 3 phase merlin gerlin board) into whatever the instructions say is needed? (eg 30mA RCD)

3. I get a little confused by the role of the neutral in polyphase. Does the neutral have a role in 3 phase or is it simply there to support single phase appliances?

 

[Julie.]

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Arrrhhhh

I most certainly wrote Henley, fudging autokorrect!

Edit, yup it "corrected" me again!!!

 

[Risteard]

Is there a reason why I shouldn't just bypass the 300mA RCD by using the Henley blocks upstream?
Meter tails into a separate enclosure housing all the bits I need.

You can call me old fashioned but I prefer to maintain an S-type upstream for at least some redundancy and fault protection for the cables feeding the DB.

 

[partplonker]

I had always assumed that EV chargers are like old 12V charger or many 3-phase UPS where they would use all phases to generate the DC for charging, but I guess they supply AC to the EV for that?

Yes, they supply AC straight to the EV for it to do the DC conversion. It's also worth mentioning that 95% of electric vehicles cannot handle more than 11kW AC or 16A per phase. There are very few EVs that can actually make use of the full 22kW.

 

[HappyHippyDad]

You can call me old fashioned but I prefer to maintain an S-type upstream for at least some redundancy and fault protection for the cables feeding the DB.

But wouldn't they already have fault protection given that its ADS with a good Ze (0.15ohms)?
I would completely agree if it was TT, it would then be a necessity.
Are you just saying it's a good idea to have as well as ADS?

 

[Risteard]

But wouldn't they already have fault protection given that its ADS with a good Ze (0.15ohms)?
I would completely agree if it was TT, it would then be a necessity.
Are you just saying it's a good idea to have as well as ADS?

Yes sorry I was referring to where a TT system exists. It wasn't intended to suggest that I consider it necessary for TN systems.
Apologies for the confusion.

 

[Julie.]

I had always assumed that EV chargers are like old 12V charger or many 3-phase UPS where they would use all phases to generate the DC for charging, but I guess they supply AC to the EV for that?

A very good point to spread the load over the phases!

EV chargers do use all three phases, convert to dc and pass this to the vehicle.

However, I think the op is installing an EV Charge Point (EVCP) which merely connects either single phase 230V or three phase 400V to the vehicle, in which case the charger is within the vehicle.

When connected to an EVCP the charge rate is limited by the lower of the EVCP (32A, 16A, 10A ) or the rating of the charger within the vehicle (might be 9.2kW)

Whereas with an EV charger, you can have very high charge capacity 50kW, 70kW, 150kW etc.

These rapid chargers are pretty big bits of kit though.

 

[pc1966]

Yes sorry I was referring to where a TT system exists. It wasn't intended to suggest that I consider it necessary for TN systems.
Apologies for the confusion.

I think the up-front 300mA RCD here is due to it coming under agricultural areas and for fire risk reduction. Supply seems to be TN-C-S.

But I agree with you that for TT systems I would always prefer a delay RCD as incomer and then RCBOs afterwards, as no *single point of failure that could leave the CPC live.

[*] Single here as in fault in a RCD not spotted by **anyone doing a periodic test, clearly it needs two fault: some L-CPC fault and then the RCBO/30mA RCD not working.

[**] AKA friends of the seal faery.

 

[pc1966]

Could you tell me why the Matt:e would need a separate isolator? It has a 5 pole mains isolator which could be used to isolate from the other electrics if a fault occurred.

If it is easy to isolate internally then you would not. It kind of depends on the trouble caused to isolate the whole system to work on the Henley blocks and feed to Matt:e versus the cost/space needed for some form of isolation.

It also depends on what the Matt:e requires in the way of any input protection / max supply PSCC. If it is fine with 100A fuses, etc, for example if has a MCB/RCBO as the only incoming connection and that can break 6kA, then not needed.

 

[HappyHippyDad]

If it is easy to isolate internally then you would not. It kind of depends on the trouble caused to isolate the whole system to work on the Henley blocks and feed to Matt:e versus the cost/space needed for some form of isolation.

It also depends on what the Matt:e requires in the way of any input protection / max supply PSCC. If it is fine with 100A fuses, etc, for example if has a MCB/RCBO as the only incoming connection and that can break 6kA, then not needed.

So it's looking like this charger just requires a 5 pin 16A commando socket and that this scenario isn't part of section 722 as its just ELV on the vehicle.

I was hoping to run past you (and others, just happened to quote you) my final (hopefully) thoughts as this is my first delve into 3 phase.

Change the 3 pole mcb in the 3 phase board for a C20. Take from this to a separate small CU housing a 4 pole Type AC RCD. From there I go to the commando socket (or possibly bypass the CU and just have the required RCD combined in the commando socket)? Probably all in 5 core 2.5mm H07RN?

I have chosen a Type AC RCD for poor reasons. There is an upstream 300ma RCD which I was trying to avoid changing to a Type A. Also, type AC RCD's are 'usually' acceptable (i.e meet the regulations) to use to protect sockets.

I am unsure how to ascertain if a type A is required as I cant get anybody at Avant who understands what DC leakage is and how likely it is with the charger/loader.

Main question is the highlighted bit though.

 

[partplonker]

So it's looking like this charger just requires a 5 pin 16A commando socket and that this scenario isn't part of section 722 as its just ELV on the vehicle.

I was hoping to run past you (and others, just happened to quote you) my final (hopefully) thoughts as this is my first delve into 3 phase.

Change the 3 pole mcb in the 3 phase board for a C20. Take from this to a separate small CU housing a 4 pole Type AC RCD. From there I go to the commando socket (or possibly bypass the CU and just have the required RCD combined in the commando socket)? Probably all in 5 core 2.5mm H07RN?

I have chosen a Type AC RCD for poor reasons. There is an upstream 300ma RCD which I was trying to avoid changing to a Type A. Also, type AC RCD's are 'usually' acceptable (i.e meet the regulations) to use to protect sockets.

I am unsure how to ascertain if a type A is required as I cant get anybody at Avant who understands what DC leakage is and how likely it is with the charger/loader.

Main question is the highlighted bit though.

If 722 doesn't apply, then my understanding is that a 30mA type AC meets the requirements for a socket < 32A and reg 411.3.3 as you said.

I fitted a 4 pole type A RCD recently (MCG branded from CEF) and there was no difference at all in cost between the type A and type AC. Both were about £50, so might as well fit a type A and you've gone above and beyond.

 

[Julie.]

So it's looking like this charger just requires a 5 pin 16A commando socket and that this scenario isn't part of section 722 as its just ELV on the vehicle.

I was hoping to run past you (and others, just happened to quote you) my final (hopefully) thoughts as this is my first delve into 3 phase.

Change the 3 pole mcb in the 3 phase board for a C20. Take from this to a separate small CU housing a 4 pole Type AC RCD. From there I go to the commando socket (or possibly bypass the CU and just have the required RCD combined in the commando socket)? Probably all in 5 core 2.5mm H07RN?

I have chosen a Type AC RCD for poor reasons. There is an upstream 300ma RCD which I was trying to avoid changing to a Type A. Also, type AC RCD's are 'usually' acceptable (i.e meet the regulations) to use to protect sockets.

I am unsure how to ascertain if a type A is required as I cant get anybody at Avant who understands what DC leakage is and how likely it is with the charger/loader.

Main question is the highlighted bit though.

I would suggest you fit type A rcd not ac

It doesn't matter that the upstream rcd is ac.

What does matter is the dc converter could inject dc into the lines, this may block an ac rcd - if you have two in series, neither would operate. If the downstream is type A then this would likely still operate.

There is usually no difference in cost, and it could be argued that since you have knowledge of the type of device intended for that circuit you ought to design for that, not fall back to the minimum standard which is likely unsuitable for this application.

It may have been different, if they had merely asked for a 16A socket outlet for general use, then a type ac whilst undesirable these days, would comply, had they subsequently used something that blocks the rcd, since you had no knowledge of the end device - no fault of yours.

However, you do actually know the intended end device. (for which ac type rcd is not recommended )

 

[Rockingit]

Agree with choosing an A type RCD for all the reasons above.......however, if you're fitting a 16a ceeform socket then you have to use a 16A CPD, not a 20A otherwise you fall foul of 433.1.1

 

[HappyHippyDad]

I would suggest you fit type A rcd not ac

It doesn't matter that the upstream rcd is ac.

What does matter is the dc converter could inject dc into the lines, this may block an ac rcd - if you have two in series, neither would operate. If the downstream is type A then this would likely still operate.

There is usually no difference in cost, and it could be argued that since you have knowledge of the type of device intended for that circuit you ought to design for that, not fall back to the minimum standard which is likely unsuitable for this application.

It may have been different, if they had merely asked for a 16A socket outlet for general use, then a type ac whilst undesirable these days, would comply, had they subsequently used something that blocks the rcd, since you had no knowledge of the end device - no fault of yours.

However, you do actually know the intended end device. (for which ac type rcd is not recommended )

Thanks Julie.

Could I ask why you don't feel it's a problem having a Type AC RCD upstream from the new Type A RCD that will be fitted? Could the Type AC RCD get blinded? The whole point in fitting a Type A RCD is because we fear we may get <6mA DC leakage. If we fear this, then how can we have a Type AC upstream as this could start to get saturated and potentially cease to operate?

Also, could you point me in the direction of any literature that suggests a type AC is not suitable for this intended use as it would be interesting to read? Or are you just going by your own knowledge?

Actually, I think I can answer my second question. I don't think a Type AC is generally suitable for items with electronic components, i.e the charger and loader! First question still stands though.

 

[Rockingit]

Thanks Julie.

Could I ask why you don't feel it's a problem having a Type AC RCD upstream from the new Type A RCD that will be fitted? Could the Type AC RCD get blinded? The whole point in fitting a Type A RCD is because we fear we may get <6mA DC leakage. If we fear this, then how can we have a Type AC upstream?

Also, could you point me in the direction of any literature that suggests a type AC is not suitable for this intended use as it would be interesting to read? Or are you just going by your own knowledge?

I assume the logic here is that any downstream requirements will be dealt with by the usual discrimination of other devices.

 

[partplonker]

Could I ask why you don't feel it's a problem having a Type AC RCD upstream from the new Type A RCD that will be fitted? Could the Type AC RCD get blinded?

Yes, you would have 2 type AC RCDs in series, so any DC leakage would blind both.

The Type A would trip on <6mA DC leakage, disconnecting the battery charger and protecting the upstream type AC.

You're right though, there is nothing in the regs that says you cannot do this. The only mention of using a particular type of RCD is when you get to special locations.

I do know that some European countries banned the use of type AC RCDs altogether in their wiring regs years ago if that tells you anything!