Addendum to Safety at 600 volts [RE-wrenches]

[Jay Peltz, Peltz Power]

Hi Phil,

One easy way to work with this problem, is to require that all hi voltage wiring
is surface. ( in conduit)  This would allow  one to easily find and keep out of
the way.

Or two another good reason for the outback series combiner box.  This would
allow someone to switch off the hi voltage and only deal with 48v nominal.

I do think the problem is going to be addressed.  Better we do it right, than
allow "them" to tell us how it should be done,

jay

peltz power

"Phil Undercuffler, Positive Energy" wrote:

> Sometimes, the greatest fear is the unknown.
>
> In the fire training I mentioned in the earlier post, the aspect that really
> caused concern was a power source that could not be disconnected--the high
> round number just added to the alarm.  I just spent some time on the line
> with John Berdner, who helped me fill in some of the blanks of what we might
> expect in a failure mode.
>
> Yes, systems are getting larger.  As systems have grown, we've moved from 12
> to 24 volts, then on to 48v--each time, safety devices and methods used
> before have become no longer listed or safe .  Suddenly, a company presents
> a product that is a quantum leap, and it takes a little time to adjust--to
> know how a system is going to work, and how it could fail.
>
> I was caught thinking that because the voltage is 10x what I'm accustomed
> to, the hazards must be linearly related.  From a property protection point
> of view, John points out that at higher voltages/lower current, the energy
> in an arc is smaller than lower voltage/high current--reducing wire heating
> and insulation destruction.
>
> Yes, becoming the current path on an array operating at 400+ volts can kill
> you dead.  But so can the same on an array operating at a fraction of the
> voltage, multiple of the current.  The lesson, of many learned, is
> respecting both and ensuring that neither we or the public are exposed to
> either.
>
> For firefighters, I'll recommend horizontal ventilation whenever an array is
> on the roof, and to focus their attention on whether there is a battery bank
> involved--a truly scary scenario.
>
> By the way, Doug, "handyman skills" was a direct quote from the guy on the
> other end of the phone.  While I have fully rewired a Victorian home under a
> homeowner permit in my years before solar and am extremely thankful for the
> opportunity, I did not take the responsibility lightly.  I searched out
> training far beyond what I would consider "handyman skills."
>
> Thank you all for the patience
>
> Enjoy the Sun!
>
> Phil Undercuffler
> Positive Energy
>
> "The most beautiful experience we can have is the mysterious....
> the fundamental emotion which stands at the cradle of true art
> and true science"  --Albert Einstein
>
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