Marking of pv stringers and feeders

[quogueelectric]

My boss keeps asking me about any code on the marking of pv stringers and or feeders is there any rules on the color ie black + white - or black - and red + for the permanent marking of the stringer and or feeder wires that you know of??

 

[iwire]

The rules are the same as for normal wiring.

White must only be used for grounded conductors and all grounded conductors must be white (or gray)

• If it is a positive ground system positive will have to be white
• If it is a negative ground system negative will have to white
• If is is an ungrounded system neither conductor can be white.

By the way, long time no see, welcome back.

 

[quogueelectric]

Marking of pv stringers and feeders

The rules are the same as for normal wiring.

White must only be used for grounded conductors and all grounded conductors must be white (or gray)

• If it is a positive ground system positive will have to be white
• If it is a negative ground system negative will have to white
• If is is an ungrounded system neither conductor can be white.

By the way, long time no see, welcome back.

Thank you so much that was very helpfull. My career is taking a different better direction and I hope to be back more often thanks for the warm welcome. My background starting in electronics in the early 80s would make a dc circuit black - red + a no brainer however someone has to order the wire and go with a color scheme I just want to steer them in the right direction thanks again......

 

[iMuse97]

Yes, welcome back. Noticed your post immediately.

 

[jaggedben]

Thank you so much that was very helpfull. My career is taking a different better direction and I hope to be back more often thanks for the warm welcome. My background starting in electronics in the early 80s would make a dc circuit black - red + a no brainer however someone has to order the wire and go with a color scheme I just want to steer them in the right direction thanks again......

In my opinion, it would be useful if PV systems followed the following convention (especially for THWN wire in raceways down to the disconnect and inverters)...

- Red for DC+ and white for DC- in negatively grounded systems.
- White for DC+ and black for DC- in positively grounded systems.
- Red for DC+ and black for DC- in ungrounded systems.

It's very common to use black and white no matter if the system is negatively or positively grounded. I've even heard of inspectors demanding it. This not only offers the observer no clue as to how the system is grounded, it also doesn't make for consistent colors with ungrounded systems. Following the red-black convention from other DC uses would help.

 

[ggunn]

In my opinion, it would be useful if PV systems followed the following convention (especially for THWN wire in raceways down to the disconnect and inverters)...

- Red for DC+ and white for DC- in negatively grounded systems.
- White for DC+ and black for DC- in positively grounded systems.
- Red for DC+ and black for DC- in ungrounded systems.

It's very common to use black and white no matter if the system is negatively or positively grounded. I've even heard of inspectors demanding it. This not only offers the observer no clue as to how the system is grounded, it also doesn't make for consistent colors with ungrounded systems. Following the red-black convention from other DC uses would help.

You can make the DC+ red if you want, and many do, but many who work in PV are electricians, and to them, black is hot.

All the USE-2/PV wire I have seen has been black, so colored tape is usually used to mark conductor polarity within the array. Some installers use red and white tape, but many just use white for the DC-/grounded conductor. The vast majority of systems are grounded DC-.

 

[BillK-AZ]

I have no problem purchasing white USE-2 or PV wire with a grey stripe for use as the grounded conductor. Ask your suppliers.

 

[iwire]

I have no problem purchasing white USE-2 or PV wire with a grey stripe for use as the grounded conductor. Ask your suppliers.

Same here, we just use white USE/RHW-2 and have no trouble getting it.

 

[Marvin_Hamon]

My understanding is that the black USE-2, due to the higher carbon content, has better long term UV resistance than any other color. While all the colors have to pass the UL test for USE-2 the test is not that stringent so in the long run at 30 years the black will hold up better.

At larger conductor sizes, 1/0 and above, that are used in larger systems with longer conductor runs black is the only color readily available. Someone might make other colors, if you want to order a mile or so for a special run.