Safety at 600v [RE-wrenches]

[Jeff Clearwater]

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Hi Graham and all,

To minimize high voltage dangers I'm opting to go with the Outback
Segmenting Breaker on all my high voltage installs.  Even though one
often can forgo fusing altogether with a 2 string or less SunnyB
system, I'm choosing to install the segmenting breaker so that the
high voltage can be cut quickly for exactly the kind of reasons you
cite.

It does add significant cost to run more than one home run to the
combiner box (especially with MCs!) and the boxes and breakers are a
bit more, but I think its highly worth it.  Not only for peace of
mind during install but also to show the customer how they can
quickly bring voltages down from 600 to 48-100 volts on the whole
array with the flip of one switch.  And of course they allow really
easy testing in case of a ground fault or failed panel.  They even
allow the system to be quickly reconfigured in case a panel goes out
so the whole system wouldn't have to stay down while replacing the
panel (assuming of course that the voltage stays within what's
needed).  With the Segmenting breaker one can even plan for switching
from a 48 volt to high voltage system in the future in case of a
change of inverter choice just by reconfiguring in the box.

And Mo Rousso turned me on to the fact that most installers he knows
are opting to shrink wrap the MC connectors - especially in high
voltage installs.  That gives a level of disincentive to to an
uneducated tradesman doing work around the panels to unplug them.  We
are also discussing ways to protect MC wires along panel backs.

And yes Multi-Lingual Signage!!!  Absolutely!

Cheers,

Jeff Clearwater
Ecovillage Design

>I am wondering if any wrenches that are installing high voltage systems
>on rooftops are also putting a ìDANGERî plaque on the roof by the
>modules?  I have noticed sizable danger stickers on the Power Light
>Power Guard systems, are these notices required?
>
>My concern is what happens in 10 years from now when a homeowner decides
>to re-roof the house.  Many roofers in L.A. have their guys remove and
>replace solar panels to avoid scheduling conflicts with solar guys.
>Roofers tend to cut every wire they see (typically sensor wires up until
>now) and pull lag bolts out with crowbars instead of un-threading them.
>I would estimate that 95% of roofing laborers in L.A. speak Spanish as
>their primary language.  I think there should be an engraved plaque on
>the roof written in English and Spanish to inform people of the danger
>potential and how to safely de-energize the system before tampering.
>
>Due to the continuing LADWP PV lockouts I need to install in CEC
>territory.  High voltage systems with Sunny Boyís seem to be working out
>the best for a number of contractors that I have recently spoken too.  I
>am just trying to figure out how to make my high voltage installations
>as safe as possible.
>
>Graham
>
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--
~~~~~~~~~~~~~~~~~~~
Jeff Clearwater
Ecovillage Design Associates
Home, Community and Village Scale Renewable Energy Systems

2525 Arapahoe Ave, Suite E4, #280
Boulder, CO 80302
1-800-440-2523 PIN7071
Fax:  720-528-7813
clrwater at earthlink.net
jeffc at ic.org

Council Member - Ecovillage Network of the Americas - http://www.ecovillage.org
Founder:  Ecovillage Research, Development, and Demonstration Program:
http://www.home.earthlink.net/~clrwater/RDD/rdd.html
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