Code Violation?

[ALLELECTRIC95]

There is a cable tray with 1/0 and large conductors as well as #6, #10 and #12 feeding various motors and lights. Are the smaller conductors located in the tray in compliance with the NEC? This is located in a coal unloading dock facility where MSHA is a governing agency.

Thanks!!!!!

 

[charlie b]

I don't understand what you think might be the issue. Are you asking whether a 1/0 and a #12 can be in the same tray? Yes they can. The rating of the insulation systems of all conductors in the same tray must be at least as high as the highest voltage applied to any of the conductors. But my guess is that the highest voltage is 480V or below, and that all conductors have 600 volt insulation systems. So that would not be a problem.

 

[Dennis Alwon]

I don't understand what you think might be the issue. Are you asking whether a 1/0 and a #12 can be in the same tray? Yes they can. The rating of the insulation systems of all conductors in the same tray must be at least as high as the highest voltage applied to any of the conductors. But my guess is that the highest voltage is 480V or below, and that all conductors have 600 volt insulation systems. So that would not be a problem.

Charlie, perhaps you can help me better understand cable trays. I have never used one but I am looking at article 392.3 and I don't see where individual wires smaller than 1/0 can be used unless it is an EGC. The op had another thread that asked a similar question with the use of #12 thhn in the tray. What am I missing here?

 

[ALLELECTRIC95]

Code Violation?

We have had an inspection at this site and they say that smaller then 1/0 cannot be in the same tray. Can anyone show us the code where we can so we can show the inspector this is acceptable?

 

[charlie b]

The op had another thread that asked a similar question with the use of #12 thhn in the tray.

The OP did not tell us whether the #12 (and the other small conductors) were "single conductors," and did not mention the type(s) of insulation systems seen in the tray. I thought the question had to do with mixing conductor sizes in the same raceway.

 

[charlie b]

We have had an inspection at this site and they say that smaller then 1/0 cannot be in the same tray. Can anyone show us the code where we can so we can show the inspector this is acceptable?

You need to clarify the two things I mention in my post above: Are you talking about single conductors, and what type of conductors are in the tray?

Dennis gave the code article above: 392.3. But it may show that the inspector is right. If you are talking about single conductor #12 THHN, then this cannot be in a tray.

 

[Dennis Alwon]

We have had an inspection at this site and they say that smaller then 1/0 cannot be in the same tray. Can anyone show us the code where we can so we can show the inspector this is acceptable?

Are the conductors in question individual conductors?

 

[growler]

We have had an inspection at this site and they say that smaller then 1/0 cannot be in the same tray. Can anyone show us the code where we can so we can show the inspector this is acceptable?

Normally you get tray rated cable to feed motors and such. It can be smaller than 1/0 but it is a cable assembly much like Romex. What I have used in the past normally has a black outer sheath and is clearly marked as tray rated cable.

I have never seen individual conductors run that are smaller than 1/0. I have seen smaller counductors run in cable tray that were part of a machine and not part of the building wiring.

You would need someone really familiar with a minning operation to see if your equipment is even covered by the NEC.

 

[ALLELECTRIC95]

Code violation??

Code violation??

Yes, they are THHN and THW single conductor going to motors and etc.

 

[Dennis Alwon]

You would need someone really familiar with a minning operation to see if your equipment is even covered by the NEC.

if this is a mining install then the NEC does not apply. Your install would not be legal with the NEC however:

Not Covered. This Code does not cover the following:
(2) Installations underground in mines and self-propelled mobile surface mining machinery and its attendant electrical trailing cable

 

[petersonra]

it might also have a bearing whether the cable tray was part of the machine or part of the premises wiring.

also sometimes people mistakenly refer to wireway as cable tray, when in fact they are two different things with different rules.

 

[growler]

if this is a mining install then the NEC does not apply. Your install would not be legal with the NEC however:

Dennis it's my understanding that some parts of a minning operation can fall under the NEC while other are exempt.

A good clear cut example would the office areas. I think they are clearly covered by the NEC.

Once you get out of the office and maybe workshops then I really have no idea where the line gets drawn.

I think anything below ground is not cover but above ground may tend to be a gray area. Depending on what the equipement is used for and location and so on.

Even if it's not covered by the NEC I have no idea what the minning inspectors are looking for nor what criteria they use.

In my opinion it's up to the minning operation to have people trained to do the work and know the rules. My father was the last person in my immediate family to set foot in a mine and that was 60 years ago.

 

[growler]

also sometimes people mistakenly refer to wireway as cable tray, when in fact they are two different things with different rules.

Good point. You would think that a wireway in a mine would offer better protection.