Multi-Contact parallel connectors [RE-wrenches]

Sun May 19 22:25:45 PDT 2002

John,

I actually wrote a retraction to my blanket statement that never made it
through my email server on Friday night. It still concerns me that many
people will misapply the connector. It takes something that is
straightforward and makes it less straightforward. It also requires very
detailed instructions on how it can and cannot be applied in the field.
Ilsco terminal blocks are fairly straightforward and are based on current
ratings. However, you still must observe bending radii and other issues
which is why some local jurisdictions require that they be assembled by a
508A shop.

I'm 100% in favor of straightforward, fully engineered, system designs. But
manufacturers routinely supply partially designed systems with partially
designed components and then throw them at the installer and say "here--wire
this according to the code." The devil is in the details of all this stuff
and my main concern is that the suppliers and manufacturers using this
equipment is not providing the level of training and instruction necessary
to have their products safely and properly applied in the field. Would you
not agree with that statement?

Bill.

-----Original Message-----
From: jberdner at sma-america.com [mailto:jberdner at sma-america.com]
Sent: Sunday, May 19, 2002 6:43 AM
To: RE-wrenches at topica.com
Subject: RE: Multi-Contact parallel connectors [RE-wrenches]

Bill:

I do not understand why you say this assembly can not ever be UL Listed.
You can certainly make code approved, parallel connections with a number
of UL Listed Products.
Ilsco power distribution blocks come to mind for one.
Several other companies make UL recognized (RU) terminal blocks as well
but I am pretty sure the Ilsco's are UL Listed.
Listing versus RU is a big deal for 508A shops and when I was at Pulse
we had to have the Gould blocks tested by UL so we could use them in our
508A combiner boxes.  This testing was required because they were only
RU not UL Listed.  Split bolts, wire nuts, etc. also qualify as ways to
make parallel connections.  Over current protection does not necessarily
have to be included in a product for it to be Listed.

Also, I think the assumption that there are few places where this
product can be used is incorrect.  They can be used with most
crystalline modules and Sunny Boys for example.  They could also be used
in conjunction with inline fuse holders with any modules and any
inverter or battery combination.  Some modules have a high UL series
fuse rating compared to their Isc rating. In that case you can certainly
make a parallel connection without any over current device.  I agree
that this is usually higher voltage thin film but I think it is better
to do the calculation than to make a untrue blanket statement that a
parallel connection is strictly prohibited.

IMHO, parallel connections always add cost and complexity to a system
but there is nothing in the code that prohibits parallel connections.

One other thing to consider: Once you make a parallel connection you
have created a PV output circuit on the side away from the modules. Now
you have to consider the code requirements for that as well.  Some of
the exceptions the code allows for PV source circuits (one series
string) do not apply to output circuits (more than one series string).

If you have any questions, or if I can be of further assistance, please
do not hesitate to contact me.

Best Regards,

John Berdner
Phone: 530.273.45595
Fax: 530.274.7271

-----Original Message-----
From: Bill Brooks [mailto:billb at endecon.com]
Sent: Friday, May 17, 2002 11:57 AM
To: RE-wrenches at topica.com
Cc: Chuck Whitaker
Subject: RE: Multi-Contact parallel connectors [RE-wrenches]

Ryan,

This is precisely why that assembly is not, nor ever can be, a UL-listed
item. It could be a UL-recognized item that becomes part of a fully
UL-listed system package, but that is a very different situation. There
are
a few places where that assembly can be used in a code-approved fashion
and
will not void the UL listing of the modules (max series fuse rating for
amorphous silicon modules). But in most applications (crystalline
silicon) a
parallel connector is absolutely prohibited.

Bill.

-----Original Message-----
From: Ryan Mayfield [mailto:ryan at energyoutfitters.com]
Sent: Friday, May 17, 2002 7:45 AM
To: RE-wrenches at topica.com
Subject: Multi-Contact parallel connectors [RE-wrenches]

Wrenches,

I have a sample from Multi-Contact of their "branch plugs and sockets"
for
parallel connections of modules but there is no UL listing on them. I am
hesitant to use a non listed product and was curious what others are
doing
to get around this problem. Do you only bring down conductors off series
connected panels? Is there another product out there that has a listing
for
parallel connections? Thanks in advance.

Ryan

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