[RE-wrenches] PV Recombiner

Wed Oct 12 11:36:51 PDT 2016

Drake:

Your point brings to mind the evolution of the BOS cabinet:

1.    In the good old days of the SW inverter, the DC cabinet was all you
got, and it was grossly inadequate.  Off-the-shelf load centers were the
only choice for the AC side.  AC bypassing was a relatively new concept but
it could be done.

2.    Prior to having an approved inverter, Outback manufactured a
brilliant system of BOS that fit the SW, the DR and the future FX series of
inverters (the PS series).  I believe BoB Gudgel is responsible for this
design and it was genius.

3.    Even with improved BOS, there are the shortcomings we have been
discussing.  There is always room for improvement and I am hoping our
discussion drives more of that.

I too believe that plug-on AC breakers are the superior alternative.  They
are cheap and readily available.  Generally two load centers are required,
one for generator fed and one for inverter fed.  GTBB systems might call
for a third panel: utility fed.  Bypass is the only issue that calls for
considerations out of the ordinary for standard load center installations.
Most panel manufacturers provide limited interlock methods.  Where we need
to interlock more than two breakers we fab our own slides.  Sure, they are
not “listed” but they are a simple mechanical device and I am comfortable
using them.

There are some challenges to overcome when integrating specialized inverter
equipment with standard electrical components.  For example, connecting
standard load centers to an FX inverter is problematic because the FX KOs
are so far from the mounting surface.  This is the part of the work that I
enjoy immensely.  We really want to make installations that are reliable,
efficient to install and look good.  I have a friend in the entertainment
industry that once said, “aesthetically pleasing installation are more
reliable…”  True words.

Thanks for you input.

William

[image: Gradient Cap_mini]
Lic 773985
millersolar.com <http://www.millersolar.com/>
805-438-5600

*From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
Behalf Of *Drake
*Sent:* Wednesday, October 12, 2016 6:36 AM
*To:* RE-wrenches <re-wrenches at lists.re-wrenches.org>
*Subject:* Re: [RE-wrenches] PV Recombiner

DC breaker systems should be designed similar to AC bolt on breaker systems
that are used for many commercial and industrial applications.

The explanation for the fact that these don't exist has to do with the cost
of designing and listing the equipment. There is no technical reason that a
DC enclosure needs to be any more difficult to wire than an off the shelf
AC box.

The AC breakers in any solar enclosure should certainly be standard snap on
breakers. Once the power has been inverted to AC, there is no reason  to
require anything other than standard code requirements.

Drake Chamberlin

*Athens Electric LLCOH License 44810CO License 3773NABCEP Certified Solar
PV 740-448-7328*http://athens-electric.com/

At 11:31 PM 10/10/2016, you wrote:

My students we just today complaining about the access to wires on the
panel mount breakers. The lug idea with separators might be a fix. It
definitely needs to be done differently. In class We added another inverter
to our package and trying to install another 175A breaker was a pain. We
have a few other DC breakers in there already. The whole cabinet is
basically inaccessible.

Jesse Dahl

NABCEP PV Installation Professional
IBEW Local 292 - Electrician
Electrical/Solar PV Instructor - HCC

Sent from my iPhone

On Oct 10, 2016, at 9:40 PM, Jerry Shafer <jerrysgarage01 at gmail.com > wrote:

You might want to look at the square D QO breaker line some are dc rated
and voltage rated and are panel mounted.
Jerry

On Oct 10, 2016 3:00 PM, "jay" <jay.peltz at gmail.com> wrote:

Iâ€ ll chime in here.

Yes the GSLC is a piece of junk.

However it is UL listed for the job. And while you could put together
something that would work with Airpax breakers together, but it wouldnâ€™t
be UL.

What I do is to swap out all the wires to Arctic ultra flex.  This allows
much better movement of the wires with significantly less stress on the
terminals.   And if you want to not attach wires to the back of the
breakers then you can and Iâ€™ve seen outback do it, install lay in lugs
facing outwards so you can use a screwdriver or allen key on them.  Allows
for installation and removal of wire without removal of the breaker or the
plate/breakers.  With thimbles of course. And I canâ€™t find them but I
know they make them, shields that fit between each breaker so the lay in
lugs are insulated.

jay

peltz power

On Oct 10, 2016, at 4:40 PM, William Miller <william at millersolar.com >
wrote:

Chris:

Thank you for the reply.  I think you misunderstand me.  We always use the
GSLC cabinets.  I just donâ€™t like the design concept that clutters the
cabinet with AC and DC breakers that are difficult to access and block
other components.  See photo below of a prewired GSLC Cabinet we were asked
to work in.  Not a good scenario.

We have created an installation standard using the GSLC that minimizes the
problems inherent with the design.  We run all AC leads to adjacent load
centers and we try to minimize the DC breakers in the cabinet.  It is our
goal to completely eliminate all breakers from the removable dead-front.  I
think it is pretty self-explanatory why one would not prefer to make
connections in a hard to reach location.

Our goal is to constantly improve our installation procedures to create
better, safer and more efficient installations.

Also, I donâ€™t need someone to instruct me on how to make a â€œfinishedâ€
looking install. If you are familiar with my work you know it is as clean
as it gets.  Review my web site.  Below is but one example of one of our
installs.

And lastly, â€œsuck it upâ€ is not a very complimentary phrase.  Please,
letâ€™s keep it professional.

Sincerely,

William Miller

<image007.jpg>

Figure 1 Factory wired GSLC

<image008.jpg>

Figure 2 Miller Solar installed GSLC..

<image009.jpg>

Lic 773985

millersolar.com <http://www.millersolar.com/>

805-438-5600

From: RE-wrenches [ mailto:re-wrenches-bounces at lists.re-wrenches.org
<re-wrenches-bounces at lists.re-wrenches.org>] On Behalf Of Chris Mason

Sent: Monday, October 10, 2016 3:40 PM

To: RE-wrenches < re-wrenches at lists.re-wrenches.org>

Subject: Re: [RE-wrenches] PV Recombiner

The GSLC gives the system a nice finished appearance that the customer will
understand. Suck it up and live with the imperfect world we function in.

On Mon, Oct 10, 2016 at 5:55 PM, William Miller <william at millersolar.com >
wrote:

Friends:

I am looking for a PV recombiner.  I need to accept the outputs from 3
remote PV Combiners, send those outputs through GFP circuit breakers, into
charge controllers, back thorough breaker, into a bus bar, through a main
breaker and onto a large battery bank.

I am using 2 Outback Radian inverters, but I refuse to install DC breakers
on their dead-front because wiring to studs facing away from the front is
an inferior design.  Furthermore, I see no need to run PV circuits through
the GSLC cabinets.

I looked at the Midnite MNDC15 but again, these use panel mounted breakers
with studs on the back.

Anyone know of a more thoughtfully designed PV recombiner?

Thanks in advance,

William Miller

<image003.jpg>

Lic 773985

millersolar.com <http://www.millersolar.com/>

805-438-5600

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Chris Mason

NABCEP Certified Solar PV Installer™

Solar Design Engineer

Generac Generators Industrial technician

www.cometsolar.com <http://www.cometenergysystems.com/>

264.235.5670

869.662.5670

Skype: netconcepts

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