MC connectors, warranties and PV system life [RE-wrenches]

Sun Feb 2 11:33:43 PST 2003

I was about to mention that but wasn't sure myself, so left it to question,
thinking they wouldn't possibly put something on there that was going to
rust, but I'm going to go check on it.  I agree it does look like spring
steel in the pictures I'm looking at.

-----Original Message-----
From: Joel Davidson [mailto:joeldavidson at earthlink.net]
Sent: Sunday, February 02, 2003 9:02 AM
To: RE-wrenches at topica.com
Subject: Re: MC connectors, warranties and PV system life [RE-wrenches]

I may be wrong, but the clips (good idea) look like they are made of spring
steel that rusts (bad idea).

"ASAP POWER!" wrote:

> ASE's large modules have nice twist-lok type connectors and clips along
the
> inside of the channel framing and down the sides.  They exit the j-box
into
> the channel frame (out the top) instead of out of the sides of the j-box
> with a nice water-tight gland.  The cable insulation is very thick and
much
> stiffer than any MC's offered, which allow them to tension into the frame
> channels where they meet the multiple clips integrated into the frame.
The
> nice twist-lok versions click into place and you line up the arrows to be
> sure.  An end of string loop back is provided as well which is completely
> tucked out of sight.  But when you connect your string's series modules it
> still loops out and over the frames of the two modules butted together.
So
> one should simply tuck the connection in the channel near a clip and just
> the insulated portion of solid lead is looped over.  One could also drill
a
> large enough hole in the sides of the two modules frames and that might
work
> even better for tidiness underneath the array.
>
> Peter Duchon
> ASAP POWER!
>
> -----Original Message-----
> From: keith [mailto:kcronin at lava.net]
> Sent: Saturday, February 01, 2003 12:41 PM
> To: RE-wrenches at topica.com
> Subject: RE: MC connectors, warranties and PV system life [RE-wrenches]
>
> William
>
> Granted the concerns you site in statements can exist, it is not always
> the case.  When we do our installation, I buy the UV rated tye wraps by
> the bag of 1000.  We have installations that I poke my head in
> periodically and have found no abrasions.  We generally don't have too
> many leaf problems here in this perpetual tropical environment.
> Especially considering if leaves are close enough to an array, there
> could be the opportunity for shading!
>
> I am aware of the DC arching you describe. We all are.  It is common
> every time you slowly draw your fluke 87 away from a live connection
> point and see that trailing arch.
>
> I believe the intent and scope of their evolution came from European
> manufacturers.  Perhaps they are more relaxed about design elements.  My
> personal feeling is that if these folks design some of the best
> automobiles in the world (BMW & Mercedes), this concept can't be all
> bad.
>
> Being a licensed electrician tells me it would probably be the most
> desirable to have everything in some form of conduit.  Per the last few
> posts I have inquired about, I also am trying to lower my installation
> costs (without sacrificing quality). If these multi contacts were a bad
> thing, I don't see all of the module manufacturers all climbing on
> board.  Just recently, I'm sure you know now, Siemens/Shell will have
> their modules setup for this configuration.
>
> We have high winds here in the middle of the Pacific.  It is on my radar
> screen to make sure things are not flopping in the breeze.  Sometimes
> doing conduit (pvc) installations, we have yet another problem.  It is
> the expansion and contraction of pvc due to temperature extremes.  If
> you have ever seen pvc run horizontally across the side of a home or a
> building exposed to sunlight, you can see it become a guitar string and
> bow.  Or it can shrink and pop out of its respective junction box.  This
> is perhaps due to the fact that an expansion fitting wasn't used on
> longer runs.  PVC also gets beat up from UV which makes it brittle and
> turns it to a new, lighter gray color.
>
> I am a fan of carflex (flexible conduit).  I again like to keep a
> connection a little loose for the expansion/contraction issues. It helps
> the wiring to be protected from physical damage and helps with some of
> your concerns.
>
> Perhaps the best solution to every concern would be to pool our
> collective experience together to make/suggest/design a mounting clip to
> properly support the MC cables from panel to panel etc. This would help
> with your concern with abrasion, HV fires, etc.
>
> One thing that never seeks to amaze me, are again, the people on this
> list.  We are all trying to bring this business to a higher level of
> quality and customer satisfaction.
>
> I have an idea that perhaps will reach fruition in the years to come- a
> twist lock style connector that will have a tab that lines up when it is
> "twisted and locked" in place.  This application is used often in
> industrial buildings as well as almost everyone's 5kw generator with the
> 30 amp "twist lock" male/female connector.
>
> Thanks for the lively, engaging thought process...!!
>
> Keith Cronin
> Island Energy Solutions
> 318 A Kuulei Road
> Kailua, Hawaii 96734
> 808-262-3268 Tel
> 808-263-0338 Fax
> www.islandenergy.net
>
> -----Original Message-----
> From: William Miller [mailto:wrmiller at slonet.org]
> Sent: Saturday, February 01, 2003 9:17 AM
> To: RE-wrenches at topica.com
> Subject: Re: MC connectors, warranties and PV system life [RE-wrenches]
>
> >keith wrote:
> >
> >>  When I review the MC connection concept, I realize it is a good
> >> thing.
>
> Keith:
>
> I've used the MC connectors and I'm afraid I can't agree.  I have no
> confidence in using unprotected wires on any assembly, especially one
> outdoors.  Fastening tray cable to metal structures with wire ties
> creates
> an abrasion point, rodents chew wire, leaves can catch on them and hold
> moisture and the installations look poor.  I'm sure your familiar with
> the
> propensity of high voltage DC installations to arcing?
>
> I've viewed those installations done by other contractors and by my
> crews
> and you can see the unprotected cables sagging from the backs of the
> modules, regardless of how well they are tied.  This goes against my
> instincts and my training.  I fear frequent failures in the not too
> distant
> future.  Combine this with top down infrastructure and repairs will be
> difficult.  I see electricians reaching under modules with dikes
> attempting
> to cut loose ties to find the bad connection.  How well can they tie
> these
> cables back up with the modules laying down flat?  Cheap, fast, yes, but
> not, in my book, better.
>
> William
>
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