[RE-wrenches] (RE-wrenches) Solar Repair Puzzle

[John Powell]

Hello Wrenches,

Here is a solar repair puzzle.

I am debugging a faulty and now partially non-functional grid-tie job in Southern California installed by another (non-cooperative) contractor.  One of two inverter's has failed (2 months post warranty) and I am trying to find a solution for the homeowner that doesn't involve a complete system re-install and meter main panel upgrade.  Here are the repair issues:

#1)  ARRAY DESIGN FLAW:  There are 2 inverters with single MPPTs that each serve arrays with panels facing in two directions (90 degrees azimuth apart) in the same single source circuit string.   Details:  30 KC130GT panels facing East.  18 KC130GT Panels facing South.  Each 3000 watt inverter has 1 string of 24 Panels…mixed and matched.  (and here's the kicker---10 separate physical sub-arrays…really)  (Note:  module and array wiring not "PV" rated)

#2)  INVERTER FAILURE.  One of the two inverters (A piece of crap Xantrex GT3.0 that was field-serviced for the bad capacitor in 2011) is kaput.

#3)  GROUND FAULTS:  Wet weather ground faulting on PV source circuit for failed 3K inverter (fuses blown 3 times.)  No significant voltage to ground when dry.   Don't yet have a wet wire voltage reading to find fault.

#4)  CODE VIOLATIONS.  

A)  Meter Main Buss Overload.  100 amp rated panel.  100 amp MCB.  40 amp solar breaker.  Even better…a famously flammable Zinsco buss and breakers.  28.4 amps max combined continuous inverter current.  (not likely due to the different azimuths of the array, but…you know…way over NEC 690.64.B.2).

B)  Inadequate GEC…undersized and improperly spliced all over the place.

Thus:  Is this poor old lady just hosed?   Any clever ideas to save her from a massive repair and meter main upgrade?  She is looking at 10k+ fix.  Second story steep roof… I'm stumped.  


Best regards,

Abe
-- 
J. Abraham Powell
President
Solforce Systems, Inc.
224-G South Milpas Street
Santa Barbara, CA 93103
e-mail:  abe at solforce.com




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