Discuss Zappi car charger open PEN protection in the Electrical Engineering Chat area at ElectriciansForums.net

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marcuswareham

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Hello,

As far as I can work out the Zappi car charger protects against PEN faults buy having a current sensing coil around the protective earth conductor and if a current is detected on the conductor it will disconnect the L, N and PE conductors.

just wondering how this meets the regs as in the regs it only mentions voltage monitoring devices for EV charging on PME

Also it would appear the Matt-e o-pen 3 phase verison useses 3 resistors in a wye / star configuration between the phases to give a virtual earth/star point then the voltage between the PME earth and the virtual earth is measured and if it is above 70v it disconnects the L, N & PE conductor after 4 seconds but before 5seconds.

it says in the regs that it needs to be a measurement between ture earth and the PME earth so how does this comply

Also this is the way i have worked out how both devices work, is this correct

thanks Marcus
 
Your right to get a low enough resistance on an earth electrode is not likely to happen unless you are next to the transformer.

Regulation 722.411.4.1 has a 2 new indents added in the new amendment (iv & v). Which basically says protection is provided by s different device, as long as it offers no lesser degree of protection than the other indents.

In regards to the zappi charger I believe it also has a voltage monitoring relay, as well as current sensing coil. This video shows the internal components.
View: https://youtu.be/gwmiGf6tChE
 
Your right to get a low enough resistance on an earth electrode is not likely to happen unless you are next to the transformer.

Regulation 722.411.4.1 has a 2 new indents added in the new amendment (iv & v). Which basically says protection is provided by s different device, as long as it offers no lesser degree of protection than the other indents.

In regards to the zappi charger I believe it also has a voltage monitoring relay, as well as current sensing coil. This video shows the internal components.
View: https://youtu.be/gwmiGf6tChE

Thank you for that, i have not seen that video and found it very interesting

If i ever get an electric car i will get a zappi, seems they ---- all over the o-pen device

How would you test the zappi (similar to how we have to do RCD disconnection time test)
 
How would you test the zappi (similar to how we have to do RCD disconnection time test)

There are specfic testers for testing EV chargers, they effectively take the place of a car and provide the facility to test the internal protection mechanics.

I believe Jordan @ Artisan Electric has one, I could trawl and find a video on it, if that would help
 
A basic option is the rolec charge check which simulates the car using the CP link.
A better version for more functionality is the metrel EV charger adaptor.... Can carry out all the tests and variations.
 
Another thought on the Zappi 2 car charger. It measures utilization voltage and disconnects if outside of the range of 207v-253v and for when a PEN fault occurs where the voltage remains within this range it disconnects if it detects any current flowing on the CPC

Surely this is not automatic disconnection as it requires user intervention and that intervention is a person receiving an electric shock for a very short duration from touching the EV and true earth? How does that conform

Thanks Marcus
 
Another thought on the Zappi 2 car charger. It measures utilization voltage and disconnects if outside of the range of 207v-253v and for when a PEN fault occurs where the voltage remains within this range it disconnects if it detects any current flowing on the CPC

Surely this is not automatic disconnection as it requires user intervention and that intervention is a person receiving an electric shock for a very short duration from touching the EV and true earth? How does that conform

Thanks Marcus
Automatic disconnection in this case is no different to an mcb or rcd rcbo etc. None require intervention as such to trip as they require an overcurrent or leakage of current to operate be that a circuit fault or person getting a shock. On theory the shock is for a very limited time, short enough to avoid harm hence the need for max zs and other parameters to be within the limits to achieve ads quick enough.

For the Zappi itself have a read of the faqs and datasheet on the myenergi website
 
Automatic disconnection in this case is no different to an mcb or rcd rcbo etc. None require intervention as such to trip as they require an overcurrent or leakage of current to operate be that a circuit fault or person getting a shock. On theory the shock is for a very limited time, short enough to avoid harm hence the need for max zs and other parameters to be within the limits to achieve ads quick enough.

For the Zappi itself have a read of the faqs and datasheet on the myenergi website

How do you figure? for an RCD or MCB achieving ADS in normal circumstances when the PEN conductor is intact then yes Zs etc will determine if it will disconnect in time. But you have no or very high Ze during a PEN conductor fault so any previous measuret on Ze or Zs doesnt help in this situation

If there is a PEN fault and due to phase balancing the voltage between L - N remains around the 230v mark. there can still be a dangerous potential voltage on the CPC relative to true earth. the zappi has a current sensing coil around the CPC (not like an RCD round the L & N) so if someone touches the car (CPC) in contact with true earth then the zappi will disconnect

But in order for there to be current on the CPC (in this situation (open circuit PEN conductor)) then someone needs to complete the circuit and receive a shock via touching the car

I know the zappi also incorporates an RCD and i understand how that works etc, but I am specifically talking about the additional protection for PEN conductor faults which is via CPC current sensor and voltage measurement between L - N
 
How do you figure? for an RCD or MCB achieving ADS in normal circumstances when the PEN conductor is intact then yes Zs etc will determine if it will disconnect in time. But you have no or very high Ze during a PEN conductor fault so any previous measuret on Ze or Zs doesnt help in this situation

If there is a PEN fault and due to phase balancing the voltage between L - N remains around the 230v mark. there can still be a dangerous potential voltage on the CPC relative to true earth. the zappi has a current sensing coil around the CPC (not like an RCD round the L & N) so if someone touches the car (CPC) in contact with true earth then the zappi will disconnect

But in order for there to be current on the CPC (in this situation (open circuit PEN conductor)) then someone needs to complete the circuit and receive a shock via touching the car

I know the zappi also incorporates an RCD and i understand how that works etc, but I am specifically talking about the additional protection for PEN conductor faults which is via CPC current sensor and voltage measurement between L - N
Call myenergi and ask the tech guy he explains it well
 

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