Module wiring safety [RE-wrenches]

[Joel Davidson]

<x-flowed>

There are very few high voltage (Class II) PV systems in the U.S.

Grid-connected PV is part of the grid distribution system. Unless the PV 
system is behind a fence, many, if not most, grid-connected PV systems feed 
back to the grid through wire in conduit and then to overhead or underground 
wire not in conduit. Solar module interconnect wiring and quick-connects 
that are neatly tied almost always pass inspection in southern California. 
Roof-mounted homeruns and other accessible wiring are another story. Some 
inspectors in So-Cal allow PVC conduit. Some require EMT. Some want threaded 
pipe. An inspector can judge any part of a PV system an "attractive 
nuisance" (real estate term describing a condition that can attract and 
injure children).

This discussion is interesting and a chance to complain about PV module 
manufacturers' failure to give U.S. customers what they want (j-boxes). 
However, I am concerned that the end result will be more Code requirements 
and added cost. In the meantime, Europeans are installing gigawatts of PV up 
to 1,000 volts DC running through double-insulated wire with no conduit 
while the U.S. PV industry perpetuates "there aught to be a law" mentality. 
Brothers and sisters, there's a world of difference between more laws and 
more freedom.

Joel Davidson



----- Original Message ----- 
From: "William Miller"
To: <RE-wrenches at topica.com>
Sent: Monday, January 21, 2008 9:52 PM
Subject: Module wiring safety [RE-wrenches]


>
> Friends:
>
> I guess there is one fundamental question (at least as I see it):  1. Are 
> high voltage wires safe when not enclosed in conduit?
>
> In addition, some are asking:  2. Are PV installers being held to a higher 
> standard than for other electrical installations (or at least, will they 
> be under the 2008 code)?
>
> I think the obvious answers are no and no.
>
> Take a look at question 2 first:  What other electrical system can any of 
> you cite that allows high voltage wire to be exposed to the general public 
> and not be protected by conduit?  I can not think of one.  Try running a 
> branch circuit in THHN stapled to the outside of your next job and see if 
> it passes inspection.  Heck, it's not even allowed inside a wall.  You 
> have to use jacketed cable and only for limited applications.  So, no, 
> enclosing high voltage wire in conduit is not unique to the 2008 PV code.
>
> Further, if electrical installations of any type accessible by the general 
> public require conduit and have for decades, why is this?  Well I surmise 
> that it is because high voltage electricity is DANGEROUS!  That answers 
> question number 1.
>
> No, I can not cite an example of someone being killed by a PV system, but 
> you can't deny it is possible, and do you want your system to be the first 
> one?  I fear that the human involved will not be the only fatality-- so 
> will the industry.  Envision your next 100 or more residential sales calls 
> after this hits the news.  Again, that fatality may never happen, but I 
> can't understand the resistance to making damn sure it doesn't.  I'm in 
> favor of the industry regulating itself, but that has to occur before the 
> accident.
>
> Also, the era of high voltage string arrays has been with us for only a 
> few years.  So if your logic is based on the statement, "No one has been 
> killed yet,"  that is not logic, that's gambling.
>
> What gets me is that the bottom line here appears to be:  the bottom line. 
> Many are apparently under the impression that exposed wiring is 
> significantly cheaper than protected wiring so they will fight tooth and 
> nail to maintain this practice.  With module J-boxes and a little 
> experimentation, we were able to do it cheaper, faster and better.
>
> I'm all for an industry task force to review the options, but I think this 
> has happened already and the report is out-- it's in the 2008 code.  I 
> suggest we not fight it but embrace it for the wisdom it is.
>
> William Miller


- - - -
Hosted by Home Power magazine

To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at re-wrenches.org

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------


</x-flowed>