no safe modules for ground-mounted arrays[RE-wrenches]

[John Raynes]

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William,

I agree completely, let me take it a couple steps further.  Anyone who's 
ever rolled their own tiltable ground mount rack system from basic aluminum 
angle learns the hard way that maintaining clearances over a wide range of 
tilt can be tricky, at least for the novice.  Something or other ends up 
binding or not clearing properly at some angle.  My point is that the 
problem of cutting and fitting custom guards will get that much more 
challenging when the requirement to accommodate tilting must also be 
met.  Also, whatever guarding and barriers have been added will likely add 
significant weight, adding more difficulty and safety concerns to the task 
of tilting a larger array section.  As I said earlier, a tiltable mount 
system that is not readily accessible, and easily and safely tiltable, is 
an array that probably will never be tilted.

So Ray, I guess another entry to your possible list of outcomes might be 
the elimination of tiltable ground mount arrays.  (Tilts will still be fine 
for skyscraper poles if the owners care to try.)

The solution to this issue ultimately has to start at the module 
itself.  PV module design is probably still in its infancy.  The early 
designs that led to the basic form factors that we live with, certainly 
didn't anticipate a world where billions of PV panels would need to be 
readily deployed, while meeting tough safety standards at the same 
time.  Protective termination modules require suitably rigid mechanical 
backing, but thin fragile silicon array faces do not suffice in this 
regard.  Europe and perhaps other countries apparently have determined that 
this is not an issue, but that won't be satisfactory here in the US, we all 
know it, like it or not.

We installers have to deal with this, and so do the module 
manufacturers.  J-boxes are interim solutions, MC/Tyco connectors are 
interim solutions.  It will take the module manus at least a few years to 
make the next big step, further innovation is needed.  Prodding by the 
UL/NEC communities, which I believe is already beginning, will help cause 
this to happen.  If we can provide an organized front to keep the pressure 
on, we should.  Joel Davidson posted an interesting link on RE markets a 
week or so ago about a global over-supply of PV modules on the near 
horizon.  That can only help our cause: in a buyer's market, sellers have 
to be more willing to bend, unlike the past 4 years.

In the mean time...  Module manufacturers need to maintain their 
(understandably flawed) J-box solution, as it already exists, as a real 
option for us.  Best available technology guides the practices in many 
industries, it should be a valid argument here as well.

John Raynes
RE Solar
Torrey, UT



At 12:52 AM 1/22/2008 -0800, you wrote:

>Bill:
>
>Great idea, but this one sounds like one of those easier-said-than-done 
>concepts.  Let's see-- a 5 kilowatt system has a panel area of about 400 
>square feet.  The modules are mounted on some kind of rack or rail, 
>meaning the module backs are not a wide open area but are obscured by 
>structural members.  Your suggestion sounds like a lot of material, a lot 
>of cutting and fitting and a lot of ugly.  The options are either the 
>flimsy plastic lattice like you put around your deck or chain link 
>fencing.  Neither sounds good to me.
>
>Instead, I think we are asking that module manufacturers design PV modules 
>like... like... like electrical equipment.  You know, with knockouts and 
>all of that.  That way, we can go down to the local electrical supply and 
>get the right, listed stuff to safely interconnect our high voltage 
>modules.  This in lieu of special ordering a constantly changing version 
>of the proprietary, expensive and hard to obtain wire and connectors that 
>ironically, offers little protection.
>
>Instead, most of us are becoming glorified stereo system installers, just 
>plugging and playing.  And hoping no one gets bit.
>
>Respectfully,
>
>William Miller
>
>
>At 10:32 PM 1/21/2008, you wrote:
>
>>All,
>>
>>I guess I'm wondering why everyone is getting worked up about the issue of
>>protecting wiring. It seems to me that if you prevent access to the back of
>>the modules with a non-conductive material (wood lattice or PVC) that you
>>have met the intent of the NEC. I may be wrong on this, but many inspectors
>>agree with me on this. If you build a ground-mount structure, enclose the
>>back sides of the array with something that allows airflow, but does not
>>allow kids getting into it.
>>
>>Bill.
>
>
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