Gray Flex [RE-wrenches]

[Bill Brooks]

Jay,

Are you suggesting that the National Electrical Code is not exhibiting
common sense? I am not going to go into detail to defend it, but this is not
a solar-specific issue. I do measure back-of-module and junction box
temperatures on my solar modules and see high temperatures of 70C on the
back-of module and 65C in the junction box. My array is an open rack
installation. On a roof, those numbers could easily be 10C hotter.

As far as wet and 60C, that is a piece of cake. If you have not witnessed
conduits filled with water in array installations, than you have not seen
enough real world applications. Regardless, the code requires that all
outdoor conduit and wiring must be wet rated and the wet rated numbers must
be used. If you want to employ an electrical engineer and make a case to use
something else, have at it.

Why are we arguing about this. The code happens to be fairly clear on this
and the stuff is available at a good electric supply house (not Home
Despot). I can imagine that Bob-O has not seen the temperatures that we see
routinely in the Central Valley of California, but I have real data to back
up my position.

What is amazing to me is the number of poorly performing PV systems in
California. Many of the deficiencies are due to lack of design experience
and the poor quality of installation. I will not name names or get personal,
but our whole industry needs to pick up a few notches if we are going to
remain credible in public's eye. We should all be striving to make our
installations conform to the code regardless of our personal opinions about
whether we think we know more than the code developers or not. There is a
forum to deal with code issues and you should take it up with them.

Practical, real world, real data, and common sense tells us to use 80C
wet-rated flexible conduit. SMUD has dozens of systems where the cheap 60C
conduit is falling apart on the roof. Don't believe me, get in a vehicle and
drive around Sacramento for a few days.

Let's choose our battles wisely with our local authorities. If they are okay
with you using 60C flex, go ahead and take the risk if you like. Please
don't pick a fight with them if they call you on it, however--I think they
are right.

Bill.


-----Original Message-----
From: jay peltz [mailto:jay at asis.com]
Sent: Wednesday, April 25, 2001 8:43 AM
To: RE-wrenches at topica.com
Subject: Re: Gray Flex [RE-wrenches]


Hi Bob-O,

Its amazing to see such lack of real data and  a lack of common sense being
applied to real world situations.

60C and WET  isn't going to be found in nature, maybe in an industrial
situation
though. ( OK so you guys doing work around volcanos better get the hi temp
stuff).

And what about the flex on a black flat roof in So Cal ( where you can
really fry
and egg), I'd say thats just a bit above the 56C you measured.

And so what happens??  Does this product melt when it gets wet?  What is the
concern here with the wet?  You are using ( right!) wet rated wire inside
the
conduit??


When I cornered John Wiles on this and I pushed him hard, he responded with
well
the flex will pull out of the fittings at high temps so we can't use it.

So lets put a sticker that says " NOT A HAND HOLD"  that ought to take care
of
it!!

common sense rules!!

jay

peltz power



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