[RE-wrenches] how would you measure a partial short circuit

[Nick Vida]

Hi Bob,

thanks for thinking about my question!

I landed  the fuses and put the fuses back in (not it- typo) on my sma  
disconnect, and there was an arc across the fuse holder. Seems like it  could 
have been closing a short circuit on the bus once the parallel  connection was 
made.

--------

Hi Bill,

Although I am not entirely sure there is no ground fault,
I took the conductors off the terminals so they were in free air, and measured 
pos to neg, pos to ground, neg to ground on both strings, and all I saw was the 
taper towards 0 from about 20 vdc, and no steady voltage anywhere but pos to 
negative. That makes me think the voltage is in a short circuit somewhere.
I cant yet make any conclusions about the wiring mistake because I had no access 
to the pull box where the different parts of the strings were connected to each 
other and to the home run. I do think there might be a short circuit between 
strings because when the fuse went back in there was an arc on the fuse holder 
as if there was a short circuit instead of a simple parallel connection. I guess 
it might have had to do with the 2 different voltages, but there is voltage 
'missing' somewhere.

Thanks for thinking about my question.

------------

Bob,

re: inverter capacitors charging, I havent seen that much of an arc with SMA 
disconnects, and the switch was in the off position, so I dont think there was 
any signal path to any real electronics. I always pull my fuses and do not 
replace them until everything is landed and hot and the voltages look proper 
when I install, and this arc was way out of range of normal.

re: backfeeding, I just suspected that too while thinking about your responses, 
and yes the 2 voltages were different by about 200 volts.

Thanks for the thoughts Bob.
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