Tray Cable

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jmellc

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Durham, NC
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Facility Maintenance Tech. Licensed Electrician
Does anyone see a logical pattern in wire colors for tray cable? Colors don’t make sense to me. A lot of the 3 wire has black, red and blue. I haven’t seen much 4 wire but 5 wire is often black, red, blue, orange & yellow. Not sure about other variations.
It seems to me that green & white should always be basic colors. Most pulls need a ground & many need a neutral so why should we always have to color phase them? Plus, I’ve rarely seen any consistent method of which wires to phase. I’ve worked places where every EC in town has been there & you never know what you will find. I’ve seen a few small mishaps, fortunately nothing destroyed.
 
jmellc said:
Does anyone see a logical pattern in wire colors for tray cable? Colors don’t make sense to me. A lot of the 3 wire has black, red and blue. I haven’t seen much 4 wire but 5 wire is often black, red, blue, orange & yellow. Not sure about other variations.
It seems to me that green & white should always be basic colors. Most pulls need a ground & many need a neutral so why should we always have to color phase them? Plus, I’ve rarely seen any consistent method of which wires to phase. I’ve worked places where every EC in town has been there & you never know what you will find. I’ve seen a few small mishaps, fortunately nothing destroyed.
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That’s a really good question, it sure would be nice to leave the phasing tape in the tool bag.
 
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Here is a picture of a motor I terminated back in 2016 on an oil tanker. It was a lot of 3-phase with black/white/red. There were hardly any EGCs in the cables. I believe this was to the Japanese Industrial Standard. Granted, I had just come to the US from Germany so I didn’t know what I was looking at but I remember installing bonding jumpers from the hull to enclosures at the end before commissioning.

Back in Germany and on European machinery installed in the US I have mostly dealt with all black conductors and one green or green/yellow. 18-16C for example if I remember correctly (18 conductors at 16AWG) Now mind you the letters NEC didn’t mean anything to me during these times. I want to think that any combination of colors can be had for manufacturers according to different standards and preferences.

In what circumstances do you deal with Tray Cable? Branch circuits, instrumentation, receptacles?
 
Those 18 black conductors would have been marked numerically in white writing on the conductor.


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Christoph said:
63a203e52cdd9ef39de88c98ddb86eeb.jpg


Here is a picture of a motor I terminated back in 2016 on an oil tanker. It was a lot of 3-phase with black/white/red. There were hardly any EGCs in the cables. I believe this was to the Japanese Industrial Standard. Granted, I had just come to the US from Germany so I didn’t know what I was looking at but I remember installing bonding jumpers from the hull to enclosures at the end before commissioning.

Back in Germany and on European machinery installed in the US I have mostly dealt with all black conductors and one green or green/yellow. 18-16C for example if I remember correctly (18 conductors at 16AWG) Now mind you the letters NEC didn’t mean anything to me during these times. I want to think that any combination of colors can be had for manufacturers according to different standards and preferences.

In what circumstances do you deal with Tray Cable? Branch circuits, instrumentation, receptacles?
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Usually receptacles but also lighting & other items.
 
There are a few different color codes used for tray cable conductor identification. This is the one I have seen the most. There is another one that works the same way, but the six base colors are black, white, red, green, orange, orange and blue.
You can see all black with printed numbers.
 
don_resqcapt19 said:
There are a few different color codes used for tray cable conductor identification. This is the one I have seen the most. There is another one that works the same way, but the six base colors are black, white, red, green, orange, orange and blue.
You can see all black with printed numbers.
Click to expand...
I don’t think I’ve ever seen a green wire in any cable. I have see a bare ground in some of the larger sizes, such as 400 or 500 MCM. That stuff is s a monster. I’ve seen it a few times, 3 or 4 conductor plus ground. Yes, I think all black with printed numbers.
 
From what I’ve seen most all cables after size 10AWG than go from colored to just numbers.

Another thing to add to tray cable which is a common violation I have even done myself. Engineer will up size conductor size for say a 20amp lighting circuit for voltage drop. Cable still has reduced equipment grounding conductor in size due to the industry standard I guess.
 
The tray cable manufacturers have tables of standard colors they offer and “custom” is also an option. But the thing is that unless you meet minimum order requirements (usually 2,000 on larger specialty runs, 10,000+ feet on others) you can’t order from them. Plus usually the back order log is 8-12 weeks so really you are scheduling a place in the queue. Plus pricing is very good if you haven’t seen manufacturer direct prices BUT it is usually tied to day COMEX so you don’t know what you are going to pay until it is produced.

So most people are buying from a consolidator like Southwire or Omnicable or Anixter. Those vendors are buying day 10,000 to 50,000 feet at a time to stock and then they cut off and send you your order from stock. They stock whatever is popular. There is a lot more call for 240 and 208 voltages and colors than 480, and industrial customers are a lot less picky. Either way identification by tape or sleeves is legal without regard for wire gauge. The mandatory color code rule is for single core cables.

That being said it is MUCH less time consuming to buy a roll of 4/C MC in “high voltage” colors than to waste time taping or sleeving it. We have no problems getting it in BOY+G.

As far as grounding it depends on the use (service vs feeder) as one just has a minimum based on MCM and the other based on load. But regardless the ground isn’t supposed to have any appreciable load on it except during a fault in which case VD doesn’t matter anymore because it’s already shorted. The exception here is radio transmitters and VFDs. In a radio the ground can carry just as much power as the antenna. In a VFD the ground carries the return current of the VFD that is often more than a few amps. Highest I’ve measured so far is 90 A peak but that’s rare. Most are a few amps at most.
 
paulengr said:
As far as grounding it depends on the use (service vs feeder) as one just has a minimum based on MCM and the other based on load. But regardless the ground isn’t supposed to have any appreciable load on it except during a fault in which case VD doesn’t matter anymore because it’s already shorted. The exception here is radio transmitters and VFDs. In a radio the ground can carry just as much power as the antenna. In a VFD the ground carries the return current of the VFD that is often more than a few amps. Highest I’ve measured so far is 90 A peak but that’s rare. Most are a few amps at most.
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The issue is where the ungrounded conductors are larger than what is normally required for the OCPD, in which case the rule in 250.122(B) requires a proportional increase in the size of the equipment grounding conductor for that circuit, something that you don't have in a standard cable.
 
Dsg319 said:
From what I’ve seen most all cables after size 10AWG than go from colored to just numbers.

Another thing to add to tray cable which is a common violation I have even done myself. Engineer will up size conductor size for say a 20amp lighting circuit for voltage drop. Cable still has reduced equipment grounding conductor in size due to the industry standard I guess.
Click to expand...
I’ve not seen reduced ground in any #12 or 10 cable. I think I’ve seen #8 with a 10 ground, not unusual. The large sizes have whatever ground you would normally pick from the charts.
 
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