Friends:
It is my opinion that electrical manufacturers have consistently lagged
behind the PV industry in providing specific specific hardware to meet 690
requirements. For example, we have an installation in progress with 3
XW6048 inverters. We need this many inverters for battery back up of
essential equipment in an agricultural business. The three inverters have
a capability of feeding 75 amps back into the grid, even though the PV size
is modest. There is in place a 100 amp service. I need to upgrade the bus
bars to meet 690.64(B). I had hoped to install a 200A Meter/Main/Combo and
downgrade the main to 100 amps. My wholesaler contacted GE and was assured
that a 200 MMC was field retro-fittable for a 100 A main breaker. Alas,
after biding the job, purchasing the equipment and scheduling an inspection
and utility disconnect/reconnect, we discover that the MMC is not
retro-fittable.
Frantic calls resulted in discovering that none of the manufacturers allow
downgrading a factory installed main breaker. The common response is, "Why
would you want a smaller main breaker?" It is disappointing that 9 years
after net metering became a reality, manufacturer's still don't understand
the particular needs of the solar industry.
My research did turn up some interesting information:
1. Square D offers a "PV Ready" MMC. The data sheet for it can be found on
our resources page: http://millersolar.com/resources/resources.html Look
under Square D. The PV ready part of this service gear consists of a
hold-down for a line side feed in breaker and places to put CTs. I have
never needed the CTs, and the hold-down is no longer required in any
jurisdiction I am aware of. What is conspicuously lacking is a place for a
690.64(A) point of connection. Also lacking is a surface mount version. I
don't see that this device is PV ready at all.
2. Also available is a MMC known informally as a "Ranch Panel." The
Spec.drawing is also available on our web site at the address
above. Interestingly, this panel does have a supply side POC, but after
reading the fine print, the breaker for that POC is limited to 50 amps. My
arithmetic says a 200A residential panel can accept 40A of PV. With this
Ranch panel, I can gain a whopping 10A of PV back feed. This is
anti-climatic as I was hoping for a true supply side tap.
I am hoping that manufacturers begin to provide down-gradable main breakers
and readily accessible supply side POCs. Schneider purchased Xantrex,
maybe a Xantrex engineer (Mark?) can place a request with Square D. If
anyone on this list has connections in the industry, please pass on this
request.
Sincerely,
William Miller.
Please note new e-mail address and domain:
William Miller
Miller Solar
Voice :805-438-5600 Fax: 805-438-4607
email: will...@millersolar.com
http://millersolar.com
License No. C-10-773985
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
