MPPT 450 200 - Leakage current

I have installed MPPT RS 450 200 with Multiplus II 8000VA and BYD Batteries.

There is a leak voltage between the body of the electrical panel and earth. the leakage is only when the MPPT is charging (not in idle state). 6-7 volts are measured between the body and earth. So I guess there is a PV voltage leak from inside the RS? did anyone experience this and what is the most convenient solution.

Thank you in advance,

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wkirby ♦♦ commented · Oct 12, 2022 at 12:32 PM

Could you describe your earthing arrangents in more detail?

It would seem that the body of the electrical panel is not bonded to earth.

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M. K. wkirby ♦♦ commented · Oct 14, 2022 at 06:51 AM

Yes, you are right. when the earth cable (earth cable between the earth rod and earth bar) is removed it is showing the leakage voltage. when the earth cable is connected it is 0V, so the earthing system is doing its job.

I am just worried about the 6-7 volts leakage incase the RS is not grounded. I have shared the photo of the system and wanted to know if it is normal or the reason for it? 20221011_123003.jpg

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20221011-123003.jpg (2.8 MiB)

Mike Dorsett commented · Oct 12, 2022 at 07:11 PM

Did you test your PV array for isolation (from ground)? This should be done on any size of array, and consists of measuring voltage from PV+ and PV- to ground for each string. This should be done under at least 500w/m^2 (half nominal irradiance), and the voltage from each pole to ground should be much less than the string voltage. i.e. if the string voltage is 400V, then the voltage to ground for each pole should be <25V.

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M. K. Mike Dorsett commented · Oct 14, 2022 at 06:59 AM

thank you for the response. Yes, I did the string testing and it is ok. The RS model will show an alarm incase of isolation failure between the PV polarities and the ground and I don't think it is an isolation problem between the strings and ground. I think the leakage voltage is coming from the MPPT RS, when it is ungrounded. So, I am intrested to know if this is normal in the MPPT 450 200 RS model?

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