Megger testing Solar Panels - identifying ground fault
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- Опубліковано 7 чер 2020
- The insulation value between the solar panel frame and the MC4 circuit must be about 40 MOhms for panel to be within warranty. Anything lower than this indicates a failed panel.
Note that I turned the panel away from the sun so the MC4 connectors did not arc when I plugged them in. It is important that there is zero voltage on the string you are testing.
This is the only video I've seen showing this procedure and thanks for the tip about soapy water. I've tried pressure washing panels on the ground to force the short. I wonder if the soap helps? I guess it would allow water to seep in more quickly. Maybe next time you do this you can show what it looks like on a bad panel
So if I just have a multimeter. I set it to read ohms and then connect the mc4 connectors together and put one lead on frame and one on the mc4 and anything less than 40 mph s is bad?
Its a different machine, not a multimeter. Used to do so called Megger-testing.
Trina solar panel procedure says
What model of tester were you using?
MMMMM - it cost about $500 - hopefully you can see the model in the video?
Wat values ate bad ?
Anything below 40 Mohms will likely be honoured as a warranty return to the manufacture. Below 100 Mohms indicates a potential problem.
Anything under 40MOhms is a problem. Different suppliers will warranty a panel at different voltage leakages. Over a 100 MOhms on 1000 VDC test is a good indication that the panel is not the bad one.
@@stevedyck8023 Thank for getting back to me.
This information is very helpful !!
@@stevedyck8023 Steve where do you takes those values from. Also, why didn't megger with open leads.
Is it the same to test strings than modules?
@@elektro7tube The solar panel manufacture will specify what MG ohms they will warranty.
The reason the leads are shorted is to remove all voltage bias from the panel. Which leads into your second question regarding strings of modules. Yes, it is ok to test strings. Most inverters perform an insulation or isolation test each morning before they start producing power. The SolarEdge inverter has a 0.6 MG ohms sensitivity - I think the PowerOne inverter is about 1.1 MG ohms. When there is whole string of panels there is often more ground fault leakage.
But back to your question - why short the panel leads? If you have a 1000 VDC string and you attach a megger tester and run a 1000 VDC test you will get bad results depending where in the string there is a ground fault. So short the leads and you have 0 VDC in the PV circuit. Now you can use your megger tester to look for the ground fault ohms between ground and the PV curcuit.
Damn .
MC3 connecters... old ass panels..haha