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Discussion Starter · #1 ·
Hi all

get my first EV later this week ! Zoe 50 R135 rapid charge. Forgive the stupid question but I did search the forum and couldn’t find an answer.
Will my Zoe charge okay with a Project EV Pro earth charger ? I have read lots of comments about the Zoe being very intolerant of a poor earth.
My charger installer recommended the Pro Earth. Just hope it will work ! Anything I need to be aware of ?
Many thanks
 

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Hi all

get my first EV later this week ! Zoe 50 R135 rapid charge. Forgive the stupid question but I did search the forum and couldn’t find an answer.
Will my Zoe charge okay with a Project EV Pro earth charger ? I have read lots of comments about the Zoe being very intolerant of a poor earth.
My charger installer recommended the Pro Earth. Just hope it will work ! Anything I need to be aware of ?
Many thanks
Can your installer provide a datasheet for the exact model he is recommending. Post it on this forum
 

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There will be no problem, as the CPC for this charge point connects directly to the incoming PE, as it has integral open PEN fault protection (that's what the "Pro Earth" bit stands for). The absolute highest value of Ze should never exceed 0.8 Ω for a TN-S supply, 0.35 Ω for a TN-C-S/PME supply. This means that Zs at the charge point is unlikely to be much above about 1 Ω. The Zoe charger measures Zs during it's initialisation stage, and will only refuse to charge if it exceeds 150 Ω, so way above the possible maximum from a charge point connected to either a TN-S or TN-C-S/PME supply.

The only problems with the Zoe are for installations where there is a local PE provided via an electrode, a TT installation. You won't have one of those, as if you did there is no point in fitting the Pro Earth version of this particular charge point. A TT installation can have a PE with an earth loop impedance that is higher than the 150 Ω that the Zoe will accept, as the regs allow Ra (the earth electrode resistance) to go up to 200 Ω *. This means that a few homes that have TT supplies, or charge points wired as TT to provide open PEN fault protection, can cause issues with the Zoe if they have a high, but acceptable, value of Ra. This is usually easy to fix, just means fitting a better earth electrode, and often the problem needs fixing anyway, to make the installation safer, especially with some older installations where things have degraded over the years.


* Technically, 200 Ω is not a hard limit, the regs allow Ra to be as high as 1667 Ω for a 30 mA RCD, but the guidance from the IET is that any measured value post-installation that's higher than 200 Ω isn't generally acceptable, to give a safe margin for Ra variation with ground conditions, etc,
 

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Discussion Starter · #5 ·
There will be no problem, as the CPC for this charge point connects directly to the incoming PE, as it has integral open PEN fault protection (that's what the "Pro Earth" bit stands for). The absolute highest value of Ze should never exceed 0.8 Ω for a TN-S supply, 0.35 Ω for a TN-C-S/PME supply. This means that Zs at the charge point is unlikely to be much above about 1 Ω. The Zoe charger measures Zs during it's initialisation stage, and will only refuse to charge if it exceeds 150 Ω, so way above the possible maximum from a charge point connected to either a TN-S or TN-C-S/PME supply.

The only problems with the Zoe are for installations where there is a local PE provided via an electrode, a TT installation. You won't have one of those, as if you did there is no point in fitting the Pro Earth version of this particular charge point. A TT installation can have a PE with an earth loop impedance that is higher than the 150 Ω that the Zoe will accept, as the regs allow Ra (the earth electrode resistance) to go up to 200 Ω *. This means that a few homes that have TT supplies, or charge points wired as TT to provide open PEN fault protection, can cause issues with the Zoe if they have a high, but acceptable, value of Ra. This is usually easy to fix, just means fitting a better earth electrode, and often the problem needs fixing anyway, to make the installation safer, especially with some older installations where things have degraded over the years.


* Technically, 200 Ω is not a hard limit, the regs allow Ra to be as high as 1667 Ω for a 30 mA RCD, but the guidance from the IET is that any measured value post-installation that's higher than 200 Ω isn't generally acceptable, to give a safe margin for Ra variation with ground conditions, etc,
thanks Jeremy for the very comprehensive reply. Good to know it will actually work ! Thanks
 

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The French wiring regulations (La norme française NF C 15-100) require a lower resistance to earth. < 100Ω, than the UK's < 200Ω. This is probably the root cause of the fussy Renault charger issues (The Twizy has similar issues, not just the Zoe)
 

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The French wiring regulations (La norme française NF C 15-100) require a lower resistance to earth. < 100Ω, than the UK's < 200Ω. This is probably the root cause of the fussy Renault charger issues (The Twizy has similar issues, not just the Zoe)

The reason for that goes back to many French installations being TT, and the EDF provided disjoncteur différentiel typically tripping at between 500 mA and 650 mA, rather than the 100 ma that a UK TT supply RCD would trip at.

I would argue that the Zoe charger isn't being fussy, it's doing something that all chargers should really do as a matter of course. Checking Zs before starting to charge makes a great deal of sense, especially given the state of a fair number of UK electrical installations. Being confident that Zs is low enough to ensure that an RCD trips rapidly in the event of a leakage fault is very definitely a good thing to do, in my view.
 

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Sorry, was too hasty with the send. Not the RFID version.

Based on the datasheet alone, I see the following deficiencies

1/ No IK (impact energy) rating specified. How Robust?
2/ No explicit mention of PEN loss (loss of combined DNO neutral/earth) protection
3/ It doesn't state the product design standards other than IEC 62196-2,Type 2. The CE mark might/would only apply against this standard.

4/ The internet security would need to be investigated separately
 

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Based on the datasheet alone, I see the following deficiencies

1/ No IK (impact energy) rating specified. How Robust?
2/ No explicit mention of PEN loss (loss of combined DNO neutral/earth) protection
3/ It doesn't state the product design standards other than IEC 62196-2,Type 2. The CE mark might/would only apply against this standard.

4/ The internet security would need to be investigated separately

The Pro Earth model does have open PEN fault protection. Not sure about impact resistance, but then most charge points aren't as impact resistant as they are supposed to be. Pretty sure there are only one or two makes that meet that requirement, but no one seems to enforce it.
 

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The Pro Earth model does have open PEN fault protection. Not sure about impact resistance, but then most charge points aren't as impact resistant as they are supposed to be. Pretty sure there are only one or two makes that meet that requirement, but no one seems to enforce it.
It's a cheap and nasty EVSE, don't expect too much.
 

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Thanks all for the discussion and replies.
Hi, seems you have some comfort from the various replies.

Given that the datasheet has a dearth of information regarding the standards that apply to some safety critical aspects, eg the RCD functionality and the issue as to whether the CE ( CHINESE EXPORT ?) actually means anything at all with regard to this same functionality, on-site testing is an area that needs care. Obviously onsite testing is not a substitute for proper design ( of say RCDs) and you might find that the installation contractor is not keen to highlight problems with kit he has himself supplied. As usual, go into these things with your eyes open.
 

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Discussion Starter · #17 ·
Hi, seems you have some comfort from the various replies.

Given that the datasheet has a dearth of information regarding the standards that apply to some safety critical aspects, eg the RCD functionality and the issue as to whether the CE ( CHINESE EXPORT ?) actually means anything at all with regard to this same functionality, on-site testing is an area that needs care. Obviously onsite testing is not a substitute for proper design ( of say RCDs) and you might find that the installation contractor is not keen to highlight problems with kit he has himself supplied. As usual, go into these things with your eyes open.
Thanks Freddym. I do appreciate your comments and insight, clearly as part of the installation process I will ensure that the contractor does answer some of the concerns raised and also ensure that it is functioning properly. There are a lot being fitted now, screwfix and tool station also now sell them.
 

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I would argue that the Zoe charger isn't being fussy, it's doing something that all chargers should really do as a matter of course. Checking Zs before starting to charge makes a great deal of sense, especially given the state of a fair number of UK electrical installations. Being confident that Zs is low enough to ensure that an RCD trips rapidly in the event of a leakage fault is very definitely a good thing to do, in my view.
Yes its is a good idea, but to be fair to the others it is far more important for a zoe than most. Most other OBCs I have seen bereakdowns/schematics for (tesla, nissan, hyundai, kia) all have galvanic isolation between the AC and high voltage DC bus (they are all basically just scaled up SMPS with water cooling to keep the size down).

The fast AC charging zoes don't have any isolation here. They just a have rectifier feeding the inverter (running in the 'regen' direction ) via the motor stator windings (acting as inductors for a giant boost converter). That's a hell of a lot more cable and components that could lead to an isolation fault than hence the higher need to take precautions.
 
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