TC-ER Pigtails

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Willsafety

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We have a new system installed at our plant that was installed by outside contractors. The system has two sets of three 480v motors. For ease of maintenance, the contractors about 3' length of TC-ER cable to make a pigtail from the motor to the disconnect. I'm at odds with some of our department electricians because I believe the pigtails are wrong according to Art. 336.10(7) of the NEC. I understand that the pigtails are less than 6' so the support rule shouldn't apply. But the requirement for installation in cable tray and protection still should apply. Are my assessments correct?
 
TC-ER is allowed to be run outside of cable tray, but must still be properly supported and protected from (i.e. not exposed to) damage.

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Willsafety said:
We have a new system installed at our plant that was installed by outside contractors. The system has two sets of three 480v motors. For ease of maintenance, the contractors about 3' length of TC-ER cable to make a pigtail from the motor to the disconnect. I'm at odds with some of our department electricians because I believe the pigtails are wrong according to Art. 336.10(7) of the NEC. I understand that the pigtails are less than 6' so the support rule shouldn't apply. But the requirement for installation in cable tray and protection still should apply. Are my assessments correct?
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IMO, not exactly, but a strong case could be made that this installation does not comply with the exception for other reasons. It appears that you can run up to 6 feet unsupported but it looks like the assumption is that one end of the TC is coming out of the cable tray, even if it's running to equipment, and not another cable tray. So, [cable tray >>>TC-ER>>> equipment], OK, [equipment >>>TC-ER>>>equipment], NG. If you want to argue "What's the difference if one end comes from cable tray or equipment?" I'm with you, but the code doesn't appear to think so.
 
FWIW and no more than that, TC-ER cable is the latest favorite of mini-split A/C manufacturers and installers to run from the outside unit to the inside unit.
They are slowly coming to accept that SO type cords are not approved, and TC-ER seems to be acceptable to many AHJs for this application.
Not all ECs are comfortable with it, of course, and it has never been acceptable to DIY the installation.

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At our facility we have thousands of feet of TC-ER cable, power and control. But this new installation kind of rubs me the wrong way. Some departments here rather you be concern about equipment in your own department but it going to be addressed, it just not priority. Now that I'm home, I'll better explain my point of view.

Field constructed 480v extension cords or motor pigtails using TC-ER cable seemed to be clearly in violation of Article 336 of the 2014 NEC. I did not mention 480v extension cords in my first post but I see some being used during outages. I really don't want to type the entire text of Art. 336.10(7) and the Exception but I'll hit the high points as I state my position.

Section (7) gives the requirements for installing type TC cable in a situation where the cable might be subject to physical damage:
1. That cable must be TC-ER and have the markings,(the pigtails have the markings)
2. Shall be permitted between a cable tray and the utilization equipment or device. (There is no cable tray in the area,but we have the utilization equipment or device which is the motor. The pigtail is made up in the motor terminal housing on one end and a 480v attachment plug on the other end.)
3. The cable shall be secured not exceeding 6'. (Since the pigtails are only about 3' long, I don't have an issue here)
4. The Cable is to be protected from physical damage using mechanical protection such as struts, angles or channels. (I don't think a closet or room meet the intent of the code, which is where these motors are installed.)
The Exception has similar language but it refers to a situation where the cable is "not subject to physical damage". Still it has the requirement for a cable tray to be in the installation. "shall be permitted to transition between cable trays and between cable trays and utilization equipment". In this installation the cable runs from the motor to the attachment plug, in which I believe is not supported by the code.
I would love to hear the opinions of other readers.
 
Willsafety said:
We have a new system installed at our plant that was installed by outside contractors. The system has two sets of three 480v motors. For ease of maintenance, the contractors about 3' length of TC-ER cable to make a pigtail from the motor to the disconnect. I'm at odds with some of our department electricians because I believe the pigtails are wrong according to Art. 336.10(7) of the NEC. I understand that the pigtails are less than 6' so the support rule shouldn't apply. But the requirement for installation in cable tray and protection still should apply. Are my assessments correct?
Click to expand...

Some reasonable assumptions have to be made but in most instances, three feet of exposed TC-ER cable will not be exposed to damage.. you have to assess on a case by case basis.
 
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