Cables out of Cable Tray

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bdss396

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Hi guys, on a recent inspection it was noted the some 4160v cables feeding into the top of a sub leave the cable tray and weren't in a conduit. The cable tray 90's down and is mounted to the top of the sub, but the 4/0 cables gently radius about 7" outside the cable tray and enter the sub through a insulated bushing. One of the more knowledgeable guys here told me that he thought that was O.K., but couldn't give me any code reference to back it up. The height is about 7'8" up. It's not exposed to physical damage in this location. I've looked at article 336 and article 392, but don't see much that I'd consider concrete. 336.12 does refrence back to 336.10(7), but I'm not sure if "secured at interals not exceeding 1.8 meters (6 ft.)" is justification to let this go ? Thanks in advance for any help you can give.
 
Nothing? I'm suprized. Anyway, after some more digging and talking with a licensed electrician, I think article 392.6 (A) makes this O.K.. Any comments ?
 
bdss396 said:
Nothing? I'm suprized. Anyway, after some more digging and talking with a licensed electrician, I think article 392.6 (A) makes this O.K.. Any comments ?
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I've never installed, or seen an installation like this, but after reading the section you referenced I would agree.
 
georgestolz said:
I've never installed, or seen an installation like this, but after reading the section you referenced I would agree.
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What about the part that says "The conductors shall be secured at the transition..." ??? The transition is where the tray is attached to the sub enclosure. [EDIT -- disregard this comment if the following applies: After rereading that paragraph, it dawned on me it is regarding "individual conductors", not multiconductor cable.]

Sounds like the cable tray installers either did a "field 90", which is simply a square 90? turn, or they used a factory 90 that is rounded but its radius is smaller than the allowable bend radius of the cable.

They would have been better off not attaching the tray to the sub, or leaving a gap in the tray. One solution may be to attach another short-of-the-cable-bend piece of tray just for these cables, that is if there are other cables that go in the main tray, and these cables need support. They are outside the tray, so cable support requirements apply.
 
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Assuming the cables to be MC? as long as the cables are tied to the last rung that is readily available, and bending radius is observed, 6' or less should be acceptable. I'm seeing this from330.30 (B) and maybe (C). Check (D) as I don't know what style cable you actually have.

Worst case scenario is having to build a unistrut rack (12" to the top) and strap gables to it.

Make sure to post the " Danger High Voltage" signs (ya I know, common sense, has nothing to do with it) it's code -110.34(C)
 
Guys' thanks for the replys. I'm at home and I don't have all my information with me. The cables are 4/0 MV cables. The cable tray was installed with a field made 90, and it's marked with 4160 volt stickers. as far as the"secured at the transisition" I was taking the last rung of the tray to be the transistion. I'll admit that might be streching it a bit. I'm figuring because this is a pre-existing situation, and becuase of it's location, this should be O.K. ? Plus it sounds to me like it's not wrong anyway. I'll check article 330.30 when I get back to work on Monday, I don't have an '05 NEC here. Thanks again
 
Guys' thanks for the replys. I'm at home and I don't have all my information with me. The cables are 4/0 MV cables. The cable tray was installed with a field made 90, and it's marked with 4160 volt stickers. as far as the"secured at the transisition" I was taking the last rung of the tray to be the transistion. I'll admit that might be streching it a bit. I'm figuring because this is a pre-existing situation, and becuase of it's location, this should be O.K. ? Plus it sounds to me like it's not wrong anyway. I'll check article 330.30 when I get back to work on Monday, I don't have an '05 NEC here. Thanks again
 
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