At 06:50 PM 3/1/2010, you wrote:
You Wrote
"This is déjà vu.....
The only other choice would be to use a contactor
to ensure PV disconnection when the grid is down
- then you could tap the PV on the load side of the transfer switch."
This is definitely deja vu all over again. A
system I designed, that disconnected 3 Sunny Boy
inverters by having contactors on the load side
of the transfer switch, had a problem. When the
contactors opened on generator exercise
cycle, the circuit breakers between the
inverters and contactors tripped. They did not
trip every time, but randomly. One or two would
trip and the other would not.
After many hours of investigation and talking
with SMA, no reason for this was ever found. The
circuit apparently had no problem with nuisance
tripping when the Sunny Boys were not
producing. We have theories, but tech support
and other professionals do not think this should happen.
If you try this method, please let me know your results.
Drake Chamberlin
Athens Electric
OH License 44810
CO License 3773
NABCEP TM Certified PV Installer
Office - 740-448-7328
Mobile - 740-856-9648
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