<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:Courier New,courier,monaco,monospace,sans-serif;font-size:12pt"><div>Hi wrenches.<br><br>I had an interesting case today that I have been thinking about since it happened. I dont have all the details because the homeownter had to leave before I was done with the service call, but here is what I do know. SB5000 with 2 strings of 15 modules. String one was 437 vdc, and string 2 was 247vdc. I decided to look for a ground fault, and I turned off the inverter. I measured for ground faults and found no evidence of anything wrong in that regard. As the homeowner was out of time and wanted me to go, I re-landed the wires in the dc disco, and when I replaced the fuses, I noticed a minor arc when one of the fuses was going it. Although I had no time to measure it, I think that there might be a partial short circuit, possibly with one complete string and some
panels of the other string, and the remaining panels on the second string. My mind was racing with how I could have measured for a partial short circuit without seeing it as an arch. I can imagine such a thing on a bigger system being a dramatic electrical event. <br>needless to say, I cant wait to get back there and go through the signal path properly and find out what the electrician did. And of course i realized that replacing the fuses in such a questionable situation was probably not the best idea.<br>Do any of you have any thoughts on how one would measure for such a thing?<br><br>nick vida<br><br></div>
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