looking for jumper pricing

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69gp

Senior Member
Location
MA
Hi,

just looking to see if anyone can recommend a supplier for 6000-1' jumpers with a male and female MC4 connectors already installed.

thanks
steve
 

69gp

Senior Member
Location
MA
Is it really too late to switch the module stringing from landscape to portrait?;)

the system is already installed and online. it looks a lot worse from looking straight up at the wire instead of this side shot

IMG_20141031_085721967.jpg
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
the system is already installed and online. it looks a lot worse from looking straight up at the wire instead of this side shot

IMG_20141031_085721967.jpg

I see. Is this actually causing massive problems, or only here and there?

Based on the price of unassembled MC4 connectors alone, I gather you are looking at upwards of $3 for each jumper. Our distributor has a 6' jumper for about $6, but I doubt they have 6000 in stock.
 

69gp

Senior Member
Location
MA
Who pays for a change out like that? Surely it is possibly poor workmanship, but how can that be enforceable other than just threatening reputation?

Not sure who will pay. To me is a code violation as the wires are bent tighter than what the code allows but that is never enforced. (the contractor installed per the drawings and the developer purchased the panels). You run into this problem quite a bit when the panels are mounted in a landscape fashion. Couple of things could have been done differently. When the order was placed for the panels they could have specified that the cables be an additional 6" long. That way it would have added another 12" overall. Or with the panels on a table they could have been wired differently.
 

SolarPro

Senior Member
Location
Austin, TX
Are the wire whip specs on the module data sheet representative of what was delivered to the site?

As sales prices have fallen, manufacturers have shortened module lead lengths in order to control costs. That can have unintended consequences in the field. It's entirely possible that the source circuit wiring plan for this site worked perfectly on paper, but not in practice.
 

SolarPro

Senior Member
Location
Austin, TX
Section 300.34 covers the general rules for conductor bending radius:

300.34 Conductor Bending Radius The conductor shall not be bent to a radius less than 8 times the overall diameter for nonshielded conductors or 12 times the overall diameter for shielded or lead-covered conductors during or after installation. For multiconductor or multiplexed single-conductor cables having individually shielded conductors, the minimum bending radius is 12 times the diameter of the individually shielded conductors or 7 times the overall diameter, whichever is greater.

The diameter of PV Wire varies considerably by manufacturer. But if you were using PV Wire with a 0.25" diameter, this section suggests that the minimum bending radius would be 2" (8 x 0.25").
 

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Garrison

Member
Location
Chicago, IL
Section 300.34 covers the general rules for conductor bending radius:

Wouldn't Art. 300.34 only apply if the system voltage was over 600V?

No less than 8 times sounds like a good idea, but I was under the impression that for PV wire and USE-2 installation methods [in systems under 600V] we should reference Art. 338 Service-Entrance Cable, and Art 334 Nonmetallic-Sheathed Cable. Art. 338.24 Bending Radius reads, "...shall not be less than five times the diameter."

Is that incorrect?
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Wouldn't Art. 300.34 only apply if the system voltage was over 600V?

It changed to 1000V in 2014. But yes.

... I was under the impression that for PV wire and USE-2 installation methods [in systems under 600V] we should reference Art. 338 Service-Entrance Cable, and Art 334 Nonmetallic-Sheathed Cable. Art. 338.24 Bending Radius reads, "...shall not be less than five times the diameter."

Is that incorrect?

Agreed on 338 if it's USE-2, though I don't think it changes the situation for the OP. (That picture shows less than five times radius.)

338 does not apply to PV wire. There would be no actual code restriction on bending listed PV wire in my opinion.

Article 334 does not apply, no way no how whatsoever.
 
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SolarPro

Senior Member
Location
Austin, TX
Wouldn't Art. 300.34 only apply if the system voltage was over 600V?

Yep, my bad. The search feature in the PDF version of the NEC is sweet feature for finding a keyword. But looking at a PDF on the screen is no substitute for opening the book when it comes seeing to the bigger picture.

338 does not apply to PV wire. There would be no actual code restriction on bending listed PV wire in my opinion.

While I agree that 338 does not technically apply to PV Wire, I don't think the logical extension of that thought is that the Code places no restriction on the bending of PV Wire.

From an inspector's point of view, it its pretty clear that the Code seeks to place bending radius restrictions on all conductor types. And that makes sense. Bad things can (and have) happened when these common sense installation practices are not followed.

If there isn't a better Code section to point to, a smart AHJ could reasonably hang his hardhat on Article 338. If an installer pushes back, that AHJ could always fall back on the "neat and workmanlike" clause in 110.12. In the latter case, the bending radius becomes "whatever the AHJ says it should be."

Point being, wiring an array with 180? bends in the source circuit wiring is just asking for trouble. If the AHJ doesn't flag the issue, the person who inspects and evaluates the project later on behalf of a potential buyer certainly should.
 

Garrison

Member
Location
Chicago, IL
Article 334 does not apply, no way no how whatsoever.

If 334 does not apply "no way no how whatsoever" where do we look for requirements on securing and supporting? Art. 338.10(B)(4)(b) is what I have been using which says, "shall be supported in accordance with 334.30." Should we be looking elsewhere for guidance?

Granted the wiring appears to be supported in the OP's photo, but that can definitely be another issue with short leads, and may be a problem elsewhere in this system.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
If 334 does not apply "no way no how whatsoever" where do we look for requirements on securing and supporting? Art. 338.10(B)(4)(b) is what I have been using which says, "shall be supported in accordance with 334.30." Should we be looking elsewhere for guidance?

Granted the wiring appears to be supported in the OP's photo, but that can definitely be another issue with short leads, and may be a problem elsewhere in this system.

I would think that the bends in the OP's picture would be more of a concern to the connections to the junction box than with the conductors themselves.
 
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