[RE-wrenches] Secure/support PV wire requirements?

Wed Dec 9 12:32:15 PST 2015

Kinetic rails offer the same channels (similar design), and we always lay
the wires in the channels when possible, which still requires either a
nylon or stainless steel cable tie to hold the wires in.
Kinetic recently revised their rails design which has an additional PV wire
channel on the opposite side from the "L-foot" attachment channel. It can
accommodate up to two RPVU90 wires.
I'll post a pic...

*Benn Kilburn *
CSA Certified Solar Photovoltaic Systems Electrician, SkyFire Energy Inc
6706 – 82 Ave NW | Edmonton, AB | T6B 0E7
P: 780-474-8992 | F: 888-405-5843 | www.skyfireenergy.com
[image: email] <benn at skyfireenergy.com> [image: facebook]
<https://www.facebook.com/SkyFireEnergy> [image: twitter]
<https://twitter.com/SkyFireEnergy> [image: linkedin]
<https://www.linkedin.com/company/283735?trk=tyah&trkInfo=tarId%3A1408655033432%2Ctas%3Askyfire%2Cidx%3A2-2-5>
 [image: google] <https://plus.google.com/+SkyFireEnergy/>

[image: SkyFire Energy Logo_horizontal]

On Wed, Dec 9, 2015 at 1:18 PM, Kirpal Khalsa <solarworks at gmail.com> wrote:

> SnapNrack.....The rails facilitate the same wire securing possibilities as
> Williams conduit.....They also have great wire clamps....Works very well on
> flush roof installs as well....I am sure there are other brands of rack
> that this will work with but we have lots of experience with the SnapNrack
> and appreciate their design with regards to securing wires underneath the
> array....
>
>
> Sunny Regards,
> Kirpal Khalsa
> Oregon LRT#25
> NABCEP Certified PV Installation Professional
> Oregon Solarworks LLC
> www.oregonsolarworks.com
> 541-299-0402
>
> On Wed, Dec 9, 2015 at 11:56 AM, Benn Kilburn <benn at skyfireenergy.com>
> wrote:
>
>> William,
>> Are you using this method on roof top systems that are parallel to the
>> roof as well?
>>
>> I don't want to bring up the question of what cost this adds to the
>> job.... but here i am bringing it up!
>> (labour and material, ...measuring & cutting pipe to length, cutting
>> slots and "clips" on table saw, filing cut pipe edges, attaching to
>> rails...)
>> There is no doubt that your method shows attention to quality and
>> workmanship however the solar biz is quite competitive and making the
>> decision to use this method and its added costs would surely cost us jobs.
>> I'm going to assume that you have been able to standardize and refine this
>> method to reduce time and costs?
>>
>> All,
>> I prefer to keep an assortment of wire management solutions handy on the
>> roof when we are supporting PV and/or micro-inverter wires....those being;
>> thick nylon cable ties *MUST HAVE metal tooth, NOT plastic tooth* (T&B
>> TY27MX), stainless steel cable ties, and a couple different types of PV
>> cable clips (heyco) that attach to the rail or module frame.
>>
>> Assuming a typical house (shingle) roof top system where bottom of the
>> mod frame rests +-4-6" off the roof surface....
>> If it is a single row of mods with the j-boxes on the high side, then
>> securing the PV wires can usually be done after the mods are mounted and
>> can be done quite well with 2-4 metal PV cable clips attached to the
>> modules upper frame. Securing the PV cable to the mod frame within 12" can
>> be done and if not then let your professional judgement guide you that it
>> is secure and protected from coming loose and subject to potential damage
>> from contact with the roof or anything else.
>>
>> If it is two rows of mods, one above the other, with the mod j-boxes
>> meeting in the middle (perhaps sharing microinverters mounted along the
>> middle rails)..... or any other combination of module layout, MC wire leads
>> or microinverter orientation... yes, it can become cumbersome at times to
>> find appropriate attachment points to secure wires... and it would be to
>> time consuming and confusing to discuss the array of possibilities here...
>> so again, you need to rely on your professional judgement to use the proper
>> material and methods to secure any and all wires.
>> This is not a task to be given to someone without an eye for detail and
>> workmanship.
>>
>> *Benn Kilburn *
>> CSA Certified Solar Photovoltaic Systems Electrician, SkyFire Energy Inc
>> 6706 – 82 Ave NW | Edmonton, AB | T6B 0E7
>> P: 780-474-8992 | F: 888-405-5843 | www.skyfireenergy.com
>> [image: email] <benn at skyfireenergy.com> [image: facebook]
>> <https://www.facebook.com/SkyFireEnergy> [image: twitter]
>> <https://twitter.com/SkyFireEnergy> [image: linkedin]
>> <https://www.linkedin.com/company/283735?trk=tyah&trkInfo=tarId%3A1408655033432%2Ctas%3Askyfire%2Cidx%3A2-2-5>
>>  [image: google] <https://plus.google.com/+SkyFireEnergy/>
>>
>> [image: SkyFire Energy Logo_horizontal]
>>
>> On Wed, Dec 9, 2015 at 11:33 AM, William Miller <william at millersolar.com>
>> wrote:
>>
>>> Rebekah:
>>>
>>>
>>>
>>> What you desire to do is not impossible.  Most module manufacturers
>>> specify supports approximately 20% form each short side.  For a 66 inch
>>> module this is 13.2 inches.  If you attach the factory PV leads to the
>>> rail, you are close to the 12 inch requirement.  If you reduce the offset
>>> to an actual 12” you are at 18% of the module width. Either way, I suggest
>>> it is close enough.
>>>
>>>
>>>
>>> How to secure the leads?  Well there are “UV resistant” wire ties, but
>>> the lack of longevity of these is starting to be realized.  There are other
>>> clips or metal reinforced ties that may be adequate.   Clips we tried are
>>> loose and/or flimsy.
>>>
>>>
>>>
>>> We have been experimenting with various procedures for over a decade.
>>> Our best method so far is to slot PVC pipe and ley the leads inside.  We do
>>> this on the table saw using dual blades.  The cut is sharp and needs to be
>>> deburred.  Once we lay the leads in we secure them with a clip made form a
>>> short section of the same slotted pie.  We cut short lengths of the same
>>> slotted pipe (3”), expand the slot using PVC cutters and it clips securely
>>> over the long sections of PVC.  See attached.
>>>
>>>
>>>
>>> William
>>>
>>>
>>>
>>>
>>>
>>> [image: Gradient Cap_mini]
>>> Lic 773985
>>> millersolar.com <http://www.millersolar.com/>
>>> 805-438-5600
>>>
>>>
>>>
>>> *From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org
>>> <re-wrenches-bounces at lists.re-wrenches.org>] *On Behalf Of *Rebekah Hren
>>> *Sent:* Wednesday, December 09, 2015 6:06 AM
>>> *To:* RE-wrenches
>>> *Subject:* [RE-wrenches] Secure/support PV wire requirements?
>>>
>>>
>>>
>>> Hi,
>>>
>>> Wondering if anyone has insight into Code requirements for
>>> securing/supporting PV wire behind the modules?
>>>
>>>
>>>
>>> I am aware that USE-2 sends you to Section 334.30 requirements for Type
>>> NM (12" from box, every 4.5 ').
>>>
>>>
>>>
>>> However, I think this is totally bogus, for 2 reasons.
>>>
>>> 1) Section 338.10(B)(4)(b) that refers the NM article is titled "Branch
>>> circuits or Feeders."  These are PV source and output circuits, not branch
>>> circuits or feeders.
>>>
>>>
>>>
>>> 2) it is nearly IMPOSSIBLE to secure the PV wire within 12" of the
>>> module junction box for many modules, especially in landscape wiring,
>>> without causing more harm than good, too tight a bending radius, stress on
>>> conductors.
>>>
>>>
>>> 334.40(B) maybe leaves a little wiggle room for concealed spaces in
>>> structures where it is impracticable to support.
>>>
>>>
>>>
>>> My big problem here is that both requirements of 334.30 are useless or
>>> harmful to PV systems. 12" to the box is often impossible, and 4.5" feet is
>>> too long to go without any support behind the array!!! I just noticed there
>>> was a proposal in 2017 to Codify the 334.40 requirements for PV cables and
>>> so I guess I only have myself to blame for not writing a better proposal at
>>> this point.
>>>
>>>
>>>
>>> Rebekah
>>>
>>> --
>>>
>>> Tel: 336.266.8800
>>> NABCEP Certified Solar PV Installation Professional™ 091209-85
>>> NC Licensed Electrical Contractor
>>>
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>>
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