[RE-wrenches] AUO ac moudles

[Bill Hoffer]

Todd

I have been researching micro inverters and AC modules for another client
and have been wondering about GFDI requirements on the DC side, according
to the NEC code an AC module may be permitted to have GFDI on the AC side
only, apparently because it has been tested as a " complete ,
environmentally protected unit ".  This is a no brainer with units like the
Exceltech AC module which is integrated into the junction box of the
module, but the AUO brand seems to be also listed as an AC module which has
normal MC4 connectors between the module and inverter (kinda jerry rigged
in my opinion).  This makes me think that there is a potential for a DC
ground fault, but because of the AC Module listing on this unit , as far as
I can tell, does not have  an integrated GFDI.  My main concern is safety
and liability, but there seems to be a real gaggle of wiring under the
module w/o a good way to protect it from damage on the roof.  There could
be a situation of a DC ground fault causing a fire on a residence that
would result in some legal finger pointing, which I would not like to have
pointed back to me as an installer!

As far as how well this AC module performs, I have no field experience.
There seems to be a real disconnect between UL 1741 requirements and what
the testing authorities are calling AC modules and the the intent of the
NEC GFDI requirements on the DC side.  I am concerned that the final
interpretation will fall on the local inspector and cause a lot of grief
for us installers.  IMHO installers need to beware of this hassle potential
and at a minimum insure that their local inspector accepts it before
installing and make sure your insurance is up to date!

It would be interesting to hear from Bill Brooks on this one!

Bill

Bill Hoffer PE
NABCEP Certified Solar PV Installer™
Sunergy Engineering Services PLLC
2504 Columbia Ave NW
East Wenatchee WA 98802-3941
SunEngSer at gmail.com Cell:(509)679-6165
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