Fellow Wrenches,

For MC cable "management", we recently used 1 1/4" Schedule 40 PVC conduit,
strapped loosely 
(to allow for expansion/contraction) to the our top rack rail with SS pipe
clamps. 
The conduit was drilled with a 1 1/4" hole saw every 18" or so to match the
spacing of the module pigtails. 
The hole edges were softened with a dremel tool. The MC cables dropped into the
conduit through the drilled holes. 
We also drilled 3/8' holes in the PVC to act as drains. Excess cable was folded
and tucked into the conduit. 
The layout was planned to allow easy access to each module's cables. Grounding
was by WEEB washers. 
This approach was much more satisfying and easier to implement than tywraps or
clips. 
The conduit dropped through the roof deck through an LB in a roof boot directly
into a metal junction box. 
EMT to the DC disco. The LB was dammed with duct seal.

Best,
Dick

Dick Ratico
Solarwind Electric
Bradford, VT



You wrote;

Chris,

I'm not saying that UV black wire ties are best. I still think that
stainless cable clips made by Wiley are probably the best option of all.
Wire ties, or your solution, should be used when cable clips can't work.

Bill.

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Chris
Worcester
Sent: Friday, December 12, 2008 10:08 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] SS zip ties

Hi all,
We have slowly evolved into using SS hose clamps with 3/4" double wall 600V
heat shrink over them to secure our wiring on our roof mount and pole mount
systems. The sharp edges can turn around and bite you! The addition of heat
shrink, which we buy in 4' lengths from Del City online along w/ the 10
packs of SS hose clamps, works great. We want our systems to go 30 years and
plastic zip ties here in the high Sierras just don't last.
It is an easy upgrade to SS zip ties and heat shrink for us. They will
probably install a lot quicker. 

Sincerely,

Chris Worcester
NABCEP Certified PV Installer
Phone: 530-582-4503
Fax: 530-582-4603
www.solarwindworks.com
chris at solarwindworks.com
"Proven Energy Solutions"

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jeff
Clearwater, Village Power Design
Sent: Thursday, December 11, 2008 6:31 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] SS zip ties

Hi Bill and all,

I've been searching for an alternative to plastic wire ties for some 
time as I'm not sure they are going to hold up over the system life 
of 20-30+ years and it'll be an ugly site to have all those wires 
drop onto the roof.

But for a flush rooftop array, an assumption to replace broken ones 
with an O&M plan as Bill suggests is prohibitive unless you want to 
pull modules and rewire all over again.  Way too much labor.

At first I was glad to see the SS ties too - but they just don't work 
that well and I too worry about the sharp edges with all the 
contraction and expansion that goes on in an aluminum based racking 
system.

On many commercial jobs we've used our own home made wire loom by 
splitting liquidtight non-metallic on a table saw.  We then use a 
self tapper and washer to screw through the back of the inside of the 
split LT to the array frame and then use one-hole straps to hold the 
wire from coming out of the slot where we want to.  I shared this 
method way back on this list and at 
http://www.home.earthlink.net/~clrwater  It's code since it's outdoor 
rated wire anyway.

I sometimes even run the LT home to a LT fitting after stopping the 
split (after providing a drain loop/low spot).  Not exactly covered 
by the code but I see no inherent violation.

I'm glad to see UniRac coming out with a zip bundle that slides into 
their rail slot  but that does only some of the job as there are many 
places we need to attach that are not directly along their rails.

I've told the folks at UniRac, DP&W, ProSolar, AEE etc. that the 
first racking company that comes out with an integrated loom or wire 
handling system will rule.  That was 2 years ago.

Still waiting!

Thanks,

Jeff Clearwater
NorthEast Solar/Village Power Design

