Backfeeding a 200 amp panel with an Outback 3648 [RE-wrenches]

[Allan Sindelar]

I am reposting this in hopes of a reply addressing this issue from Chris
Freitas.

I was at an all-day John Wiles PV/Code workshop today. This is a real issue.
As few homes have service panels larger than 200A, there's no legal way to
tap a PS1 or PS2 into a standard panel. It either has to be a second service
entrance or a downsized main breaker.

According to John (note that all of our regional inspectors were there...)
even the 50A AC breakers aren't usable at their claimed 100% duty cycle
(thus avoiding the 80% derating) as they haven't been tested and listed for
use in the Outback enclosures they're installed in. It's an issue of heat
buildup.

Chris, please address these issues for us Wrenches.

Thanks,
Allan

----- Original Message ----- 
From: "Allan Sindelar" <allan at positiveenergysolar.com>
Sent: Wednesday, October 18, 2006 10:21 AM
>
> IMHO, this is a bigger issue than it seems on the surface and I would
> appreciate further illumination from Christopher Freitas (probably next
> week, after the whoop-de-do in San Jose). Outback's PS1 system comes
> standard with 50A AC breakers, which requires either a 200A main panel or
a
> service tap. It would open up more applications if the "buy" could be 50A
or
> 60A, and the "sell" function could be through a separate breaker that
could
> be smaller; perhaps limited to the maximum available sell current after
> deration. If the two functions could somehow be separated, the range of
> applications would be increased, as it's only the sell function that is
> subject to the 120% bussbar limitation of 690-64(b)(2).
>
> As it is, the 50A breakers require a 250A main bussbar or an undersized
main
> AC breaker in a 200A panel. So far our inspectors have allowed this in
200A
> panels, but it's technically a serious limitation if enforced.
>
> Also, I believe that the Outback AC breakers are rated for continuous duty
> at 100% of rating, but I'd like to have that verified. Otherwise, 125% of
> 50A is 62.5A, which upsizes to 70A, which requires #4 AWG wire and a 350A
> bussbar rating. And now we're getting completely absurd.
>
> Allan at Positive Energy
>
> ----- Original Message ----- 
> From: "Todd Cory, Mt. Shasta Energy Services" <toddcory at finestplanet.com>
> > Buy and Sell still both go through one 60 amp breaker which is actually
> > the issue, but IMO it is curious we are dealing with a perceived only
> > possible problem of overcurrenting the load center's buss bar. The 60
> > amp current flow is in BUY mode only. The inverter is simply incapable
> > of a sustained SELL current that would overload the buss. I would love
> > to see someone try to damage a load center buss with a 30 amp inverter
> > backfeeding. I would bet big money this is impossible.
> >
>
>
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