String wire colors

[69gp]

Hi,
First time posting here, so go easy on me. I have just a few questions on string color coding for solar panels. I just finished working on a 3 meg solar site. We had 465 tables each table had 2 strings going back to a 12 circuit combiner box. The wire size was #10 copper. We used black for the positive, white for the negative and green for the ground. Total string voltage was roughly 480 VDC.

In the past few days I have been to several different solar sites ranging in size from .5 meg to 1.5 meg. The wiring size was #10 copper. All the string wiring was done in black including the ground that had two to three inches of green tape to identify it as a ground.

I know the code states that anything under a #6 must be identified by white for the grounded conductor and green for the ground.

My question is, is there an exception when it comes to solar panels that allows for this type of color coding? The way I see it its a code violation.

Also how would this apply to a bi-polar system?

Steve

 

[jaggedben]

You haven't made clear if you are talking about exposed conductors on arrays, conductors in raceways, or both. Your mention of ground conductors taped green suggests you are talking about conductor in raceways, since usually solar systems use bare copper grounding conductors in exposed locations. In the case of conductors in raceways, you are correct that it is a violation to re-mark 10awg conductors.

In the case of exposed conductors, it is not a violation to mark a conductor with white tape at terminations. This is explicitly allowed by 200.6(6). (But it would be violation to tape a small conductor green.) In addition, solar guru John Wiles has told a lot of people that non-black conductors aren't as durable in direct sunlight, so many people either use black conductors and mark them white, or use black conductors with a white strip or something like that.

There is also the possibility that one of the sites you visited was an ungrounded system, in which case there should be no white conductor (and it would be a violation to use one or mark one as such.

My own opinion is that the color convention (insulation or marking) should be as follows:

ungrounded positive PV conductor = red
ungrounded negative PV conductor = black
grounded PV conductor = white

This convention would make a lot of sense for a bi-polar system. But the only thing required is that the grounded conductor be white or marked white.

 

[69gp]

You haven't made clear if you are talking about exposed conductors on arrays, conductors in raceways, or both. Your mention of ground conductors taped green suggests you are talking about conductor in raceways, since usually solar systems use bare copper grounding conductors in exposed locations. In the case of conductors in raceways, you are correct that it is a violation to re-mark 10awg conductors.

In the case of exposed conductors, it is not a violation to mark a conductor with white tape at terminations. This is explicitly allowed by 200.6(6). (But it would be violation to tape a small conductor green.) In addition, solar guru John Wiles has told a lot of people that non-black conductors aren't as durable in direct sunlight, so many people either use black conductors and mark them white, or use black conductors with a white strip or something like that.

There is also the possibility that one of the sites you visited was an ungrounded system, in which case there should be no white conductor (and it would be a violation to use one or mark one as such.

My own opinion is that the color convention (insulation or marking) should be as follows:

ungrounded positive PV conductor = red
ungrounded negative PV conductor = black
grounded PV conductor = white

This convention would make a lot of sense for a bi-polar system. But the only thing required is that the grounded conductor be white or marked white.

Hi,
The conductors that I am talking about are all black and run exposed on the aluminum support beams that the panels are resting on. This includes the #10 black with green tape used for the ground.

The conductors are only exposed to direct sunlight for about 1foot as they span between 2 tables otherwise they are in shade all day long. By the way what would be the solution to the conductors that are exposed to sunlight? Would a UV rated split wire loom work?

Steve

 

[69gp]

Pictures of ground wiring

Pictures of ground wiring

Hi,

I loaded 2 pictures of some #10 black wire with green tape attached to a driven post. There is about 3 inches of tape wrapped to the end. The 2nd picture show the #10 black ground wires with green tape. Code violation??

Also in the 2nd those are 3/0 conductors. can you find any violations there?

Steve

 

[jaggedben]

Hi, The conductors that I am talking about are all black and run exposed on the aluminum support beams that the panels are resting on. This includes the #10 black with green tape used for the ground.

As I mentioned earlier, usually solar installations use solid bare copper grounding wire. A green insulated conductor or a green factory marking would be okay though. Taping a #10 is still a code violation AFAIK.

The conductors are only exposed to direct sunlight for about 1foot as they span between 2 tables otherwise they are in shade all day long. By the way what would be the solution to the conductors that are exposed to sunlight? Would a UV rated split wire loom work?

The code allows only USE-2 or listed PV wire. For ungrounded systems it allows only PV wire.

I loaded 2 pictures of some #10 black wire with green tape attached to a driven post. There is about 3 inches of tape wrapped to the end. The 2nd picture show the #10 black ground wires with green tape. Code violation??

I would say yes, it is a code violation.

Also that's an unusual looking piece of hardware used for the grounding attachment. Maybe it is listed for bonding both copper and aluminum and will not corrode outdoors, but I have to wonder.

Also in the 2nd those are 3/0 conductors. can you find any violations there?

If it's a grounded system, one of those conductors ought to marked white. If it's ungrounded, then it's fine (from what can be seen in the picture).

 

[69gp]

Also that's an unusual looking piece of hardware used for the grounding attachment. Maybe it is listed for bonding both copper and aluminum and will not corrode outdoors, but I have to wonder.



If it's a grounded system, one of those conductors ought to marked white. If it's ungrounded, then it's fine (from what can be seen in the picture).[/QUOTE]

On the second picture there is no bushing on the male adapter, the MA is broken and although you cannot tell by the length the green wire is only in the box by about 3-1/2".

The ground bar is tin coated copper. It's in a Cutler-Hammer 200 amp single pole combiner box. It does have a UL listed label on it.

 

[jaggedben]

Also that's an unusual looking piece of hardware used for the grounding attachment. Maybe it is listed for bonding both copper and aluminum and will not corrode outdoors, but I have to wonder.

The ground bar is tin coated copper. It's in a Cutler-Hammer 200 amp single pole combiner box. It does have a UL listed label on it.

I was referring to the grounding attachment in your first picture, the one used to ground the mounting structure.

 

[69gp]

I was referring to the grounding attachment in your first picture, the one used to ground the mounting structure.

That is a stainless steel lug with a UL label marking on it.