[RE-wrenches] Best practices for genset on premises

[Nathan Charles]

We do a lot of installation in Agricultural settings and a design pattern I
keep running into is a large genset on premises, the transfer switch is the
first peice of service equipment  and the customer wants to interconnect in
a remote sub panel because they don't want to run another set of lines.  We
generally convince them to run another set of lines to interconnect in
front of the transfer switch because that seems to be the best way of
dealing with NEC 702.5.

Inevitably the question comes up, can we use our PV generation to reduce
our generator load.  Most of the gensets we deal with don't have a
frequency range that would make it an option but we've run into a few cases
where it’s a 300-750KVA genset and it theoretically might be possible if
there was some protective relaying or something.

There is going to be a size that this makes sense, but I'm not sure what
is.  Has anybody run into this scenario and have any advice of what size
it's worthwhile dealing with the design issues or other good ways of
dealing with 702.5?

Regards,
-- 
Nathan Charles
Engineer
NABCEP Certified PV Installation Professional
Paradise Energy Solutions
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