Evolution of the Quick connect [RE-wrenches]

[John Berdner]

Phil / Wrenches:
 
I was involved with some of the discussions with J. Wiles, W. Bower and
R. Wills on 690.31 (A).  2008 690.31(A)  was added to deal with the
situation of an untrained person, a small child for example, being able
to walk up to a ground or pole mounted array and grabbing onto single
conductor cables.  Even assuming locking connectors it could be possible
to pull the wire out of a terminal box or break the wire.  This could
result in live conductors and or possible arcing during the load break. 

 
Think 5 year old hanging off the wiring jungle gym style.  I have asked
many wrenches out there if that image is ok in their minds and I have
not found one yet that thinks it is.
 
The key phrase in 690.31(B) is "readily accessible".  Rooftop PV for
example is not considered readily accessible under the NEC unless there
is roof access from an unlocked door, rooftop at ground level, etc. 
Even if you have a ground mounted array you can make the wiring not
"readily accessible".  Building a fence or putting a cover on the back
of the array, expanded metal mesh for example.  Access to the wiring
then would require you to unlock the gate or remove the metal mesh with
a tool before you could gain access to the wiring thereby making the
wire no longer readily accessible.  I would expect that the structure
and/or module guys will come up with some innovative solutions fairly
soon that meet the requirement at relatively low cost.
 
This requirement is independent of the locking connector requirement.
 
I hope that helps shed a little light.
 
Best Regards,
 
John Berdner
 
-----Original Message-----
From: Phil Undercuffler [mailto:p.undercuffler at conergy.us] 
Sent: Tuesday, January 08, 2008 11:58 AM
To: RE-wrenches at topica.com 
Subject: RE: Evolution of the Quick connect [RE-wrenches]



You say tomato, I say tomahto....

As a distributor, we've been struggling with this for some time now.
Multi-Contact makes two styles of connectors, neither of which (and
I'm
not making this up) have been officially named. Their US website
describes them as Solarline 1
(http://www.multi-contact-usa.com/products/solarline/1) and Solarline
2
(http://www.multi-contact-usa.com/products/solarline/2).

However, the MC reps tell us that Solarline 1 & 2 aren't really their
names. They prefer to call them either First vs Second Generation, or
latching vs locking. To make things even more fun, on the other side
of
the pond they go by MC3 and MC4, which is the diameter of their socket
and pin (3mm and 4mm respectively). Now doesn't that just provide
greater clarity? Or you can go by the catalog part numbers (PV-KBT3II
UR and PV-KST3II UR vs PV-KBT4/2.5 II and PV-KST4/2.5 II), which just
trips off the tongue.

If all this isn't entertaining enough, Tyco makes 5 different types of
plugs -- positive and a negative females, and positive, negative and
neutral males.

So why the change from First Generation/latching/Solarline 1/MC3 to
the
new locking standard? 690.33(C) in the 2008 NEC states that connectors
that are readily accessible and that are used in circuits operating at
over 30 volts, nominal, maximum system voltage for dc circuits, or 30
volts for ac circuits, shall require a tool for opening. MC (and Tyco)
make optional sheaths which snap over their locking connectors, which
then require a tool to open the connector.

However, in an apparent code conflict that I haven't yet wrapped my
head
around, 2008 690.31(A) states that readily accessible conductors >30
volts shall be installed in a raceway. (BTW, anyone have any good
suggestions how to make that work in this day of connectorized
modules?)
If the connectors are accessible, then you need a tool to open the
connector. If the circuit conductors are accessible, then you need to
use raceway. But if you use raceway, then the connectors shouldn't be
accessible so you don't need to meet the tool requirement.


------------------------------------------------------------
Please note new phone extension!

Phil Undercuffler
Technical Services Manager
Conergy, Inc.
1730 Camino Carlos Rey Suite 103
Santa Fe NM 87507 USA
Office | 505.473.3800 x4841
Fax | 505.473.3830
www.conergy.us 




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