TC or Tray Cable

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Stephen Tishhouse

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Kalamazoo Mi.
I have a appartment (100 apartments) project where the mechanical contractor is adding AC split units. It is in his contract to instal the head or the unit inside and the control wire to it. So he installed Tray cable with the line set to all the inside places (2 per outside unit he has 20 installed). The iElectrical inspector has came on site for my work and looked at his work, and has told him that he also needs to pull a permit for his control wire to the head in, and also that he needs to change all the tray cable. His supplier sold the TC to him. I called up several mechanical contractors and all use TC cable. I also talked to a few other inspectors in other areas and they say that they always let the TC be installed. I do see that it does not meet the NEC standards. What is your thoughts on this?


336.12 Uses Not Permitted.
Type TC tray cable shall not be installed or used as follows:
(1) Installed where it will be exposed to physical damage
(2) Installed outside a raceway or cable tray system, except as permitted in 336.10(7)
(3) Used where exposed to direct rays of the sun, unless identified as sunlight resistant
(4) Direct buried, unless identified for such use

336.10 Uses Permitted.
Type TC cable shall be permitted to be used as follows:
(1) For power, lighting, control, and signal circuits.
(2) In cable trays.
(3) In raceways.
(4) In outdoor locations supported by a messenger wire.
(5) For Class 1 circuits as permitted in Parts II and III of Article 725.
(6) For non–power-limited fire alarm circuits if conductors comply with the requirements of 760.49.
(7) In industrial establishments where the conditions of maintenance and supervision ensure that only qualified persons service the installation, and where the cable is continuously supported and protected against physical damage using mechanical protection, such as struts, angles, or channels, Type TC tray cable that complies with the crush and impact requirements of Type MC cable and is identified for such use with the marking Type TC–ER shall be permitted between a cable tray and the utilization equipment or device. The cable shall be secured at intervals not exceeding 1.8 m (6 ft). Equipment grounding for the utilization equipment shall be provided by an equipment grounding conductor within the cable. In cables containing conductors sized 6 AWG or smaller, the equipment grounding conductor shall be provided within the cable or, at the time of installation, one or more insulated conductors shall be permanently identified as an equipment grounding conductor in accordance with 250.119(B).
Exception: Where not subject to physical damage, Type TC-ER shall be permitted to transition between cable trays and between cable trays and utilization equipment or devices for a distance not to exceed 1.8 m (6 ft) without continuous support. The cable shall be mechanically supported where exiting the cable tray to ensure that the minimum bending radius is not exceeded.
(8) Where installed in wet locations, Type TC cable shall also be resistant to moisture and corrosive agents.
FPN: See 310.10 for temperature limitation of conductors.
 
The case is a lot stronger for using TC-ER than straight TC, but the letter of the code does not seem to allow that either.
This has been discussed a lot here, and the consensus is that SO family flexible cord, even when supplied by the manufacturer, is not acceptable under current code.
 
Stephen Tishhouse said:
the mechanical contractor is adding AC split units.

His supplier sold the TC to him.

I also talked to a few other inspectors in other areas and they say that they always let the TC be installed.
Click to expand...

This is frequently a sticky issue when you have the HVAC people doing that interconnect wiring. Last year I did a job where the HVAC contractor installed the TC-ER cable. I assumed they had the appropriate electrical specialty license to do the electrical work but wasnt sure whose permit it was under, if any. Turns out I got zinged on inspection for no Disco for the indoor unit. The inspector didnt care or didnt notice the TC cable. Because I am a nice guy, I just put in the discos (2).
That HVAC company owes me lunch.
 
Hi, Im working in an industrial Project for water plants. I had planned tu use TC-ER cable from the cable trays to the final equipment and cable was ordered. But I was surprised when the cable was delivered as it was TC type and not TC-ER. The situation is that there are not time margen to receive new cable, so Im thinking what to do now. Im new using the NEC code and looking into for any solution. Might be any condition where the NEC allows the TC cable in exposed run?
Thanks
 
Davidabg said:
Hi, Im working in an industrial Project for water plants. I had planned tu use TC-ER cable from the cable trays to the final equipment and cable was ordered. But I was surprised when the cable was delivered as it was TC type and not TC-ER. The situation is that there are not time margen to receive new cable, so Im thinking what to do now. Im new using the NEC code and looking into for any solution. Might be any condition where the NEC allows the TC cable in exposed run?
Thanks
Click to expand...
Type TC is not permitted in exposed run (other than in cable tray). Run it in raceway from tray to equipment. That's how it's done over here.
 
The door was opened a bit in the 2017 code with the addition of list item (9) to 336.10. At this time the door is only open for the specific application of connecting a generator for one- and two-family dwelling units. I would not be surprised to see an expansion of this to other applications for the 2020 code.
(9) In one- and two-family dwelling units, Type TC-ER cable containing both power and control conductors that is identified for pulling through structural members shall be permitted. Type TC-ER cable used as interior wiring shall be installed per the requirements of Part II of Article 334.

Exception: Where used to connect a generator and associated equipment having terminals rated 75°C (140°F) or higher, the cable shall not be limited in ampacity by 334.80 or 340.80.

Informational Note No. 1: TC-ER cable that is suitable for pulling through structural members is marked “JP.”

Informational Note No. 2: See 725.136 for limitations on Class 2 or 3 circuits contained within the same cable with conductors of electric light, power, or Class 1 circuits.
Click to expand...
This product was developed for Generac. Not sure if it is available on the open market.

They got around the 725.136 issue by using 725.136(I). The control cable within the cable has a jacket that is listed as a non-metallic jacket.
 
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Smart $ said:
Smurf tube = ENT

May be permitted, but I certainly would not use it in an industrial application. :happysad:
Click to expand...

WHY NOT? TC is used in industrial settings and all you would be doing is using the blue stuff to hide the TC. The TC is probably more robust than anything in smurf tubing is.
 
You can perform a search here for "mini-split" and see more details.
 
mini split wiring

mini split wiring

I have focused much research on the wiring challenges with these mini split units. It's not if TC or TC-ER is robust or not or if it works (it does work), it is following the NEC Code. TC or TC-ER is a non-compliant cable for this application. If inspected and the inspector is up to date on where TC or TC-ER can be used - it clearly states they can be used in a Tray or Raceway. This application qualifies as neither of those.

More provisions are in the 2017 code for broader uses of TC cable, but many states are not on that code cycle or are in the process of moving there. I find it frustrating that the distributors of the units are unaware in many markets what a compliant cable is vs. a non-compliant cable for these installations. If you were to use a cable they recommend that is non-compliant and the inspector rejects it -- you are on the hook, not the supplier.
 
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