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<font size=3>Dick:<br><br>
I disagree with your plan. To qualify as a supply side tap, the tap
needs to be on the supply side of the <u>main disconnecting
means</u>, If I understand your plan correctly, your suggestion
does not achieve this.<br><br>
Bruce:<br><br>
Your inspector is correct -- not in his interpretation of the code -- but
in the reality of implementing your plan. I wrote in this forum
recently (6/25/2009) of the difficulties we had in down-sizing a main
breaker because no manufacturer has made provision for this in
meter/main/combo (m/m/c) panels.<br><br>
In the situation cited, we had the capability of back feeding 75 amps
into a 100 amp m/m/c. There was not enough PV to allow this, but
the three Xantrex XW6048 inverters had a combined sell capability of 75
amps. In reality, for a short time after a utility outage, these
inverters could battery-sell up to the 75 amp capability. Our best
solution would be to install a 200 amp meter panel with a 100 amp
breaker. The application is an agricultural based residence, so
based on how one interpreted this, the back feed allowance would be
either 100 amps or 120 amps, enough to cover our back feed.<br><br>
We were told by a supplier that we could purchase a 200 amp m/m/c and
field retrofit a 100 amp breaker into it. We requested the supplier
contact the manufacturer (GE) and obtain confirmation of this
claim. We were assured that this was possible.<br><br>
Based on the assurances, we bid the job and won the contract. When
we purchased the equipment we found that the 100 amp breaker could not
physically fit into the 200 amp m/m/c. We spent a full day calling
GE and then other manufacturers only to find out that no one builds a 200
amp m/m/c that can fit a 100 amp main. All of the panels we looked
at were cleverly configured to not allow the smaller breaker to be held
in place.<br><br>
Has anyone out there found a 200 amp m/m/c that can fit a 100 amp
main? If so, I want to know.<br><br>
We ended up jury rigging a 100 amp main into a Square D Home-line
"ranch" panel, against manufacturer's recommendations.
The retrofit was solid, but we essentially violated the listing. I
did not like doing this, but we were in a corner.<br><br>
In my earlier post I point out the fact that electrical equipment
manufacturer's are behind the times in implementing equipment that can
adapt to the new requirements for solar electric systems. Now that
Schneider, owners of Square D, now own Xantrex, maybe there can be some
"cross-pollination" of ideas so that Square D can build meter
panels that allow installation of down-sized main breakers. I can
see no reason why it would be unsafe or unfeasible to allow this to
happen. I am cc'ing Mark Edmunds of Xantrex with this e-mail in
hopes it will draw his attention. A memo from him on Xantrex letter
head may have enough credibility to get the attention of Square D
engineers.<br><br>
Sincerely,<br><br>
William Miller<br><br>
<br><br>
<br><br>
At 04:11 AM 8/1/2009, you wrote:<br>
<blockquote type=cite class=cite cite>Bruce,<br><br>
This sounds like a good situation for a line side tap, <br>
rather than going to all the work of replacing the panel.<br><br>
Turn off main breaker at the pedestal, no need to touch the meter. <br>
At the house, pull the feeder out of the panel. <br>
Put it into a proper new junction box. Splice<br>
one set of new conductors to refeed the panel and another <br>
new set of conductors to feed a new small panel for the solar.<br><br>
Dick Ratico<br>
Solarwind Electric<br><br>
<br>
--- You wrote:<br>
Hi Folks,<br><br>
Can anyone provide code reference or advice on this question?<br>
Our customer has 100 amp service at the meter pedestal, 100 amp
main <br>
breaker feeding 200 foot underground run to a 100 amp panel at the
<br>
house. We need to land a 40 amp breaker, so are proposing to
replace <br>
main panel at house with 200 amp panel. The AHJ says we need a 200
<br>
amp main breaker in this panel, which will work, but says this
<br>
requires upsizing the feeder, main breaker at meter, and therefore
<br>
utility service to 200 amps.<br><br>
I've read on this list and elsewhere about downsizing the main
<br>
breaker in a panel to create capacity to make the 120% rule. This
AHJ <br>
says you can't put in a breaker smaller than the panel size, and
<br>
furthermore, everything upstream would have to be upsized. Is this
<br>
from the code?<br><br>
Bruce Erickson</font></blockquote></body>
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