Tray Cable terminated with a Twist Lock Plug

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eric9822

eric9822

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Location
Camarillo, CA
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Electrical and Instrumentation Tech
Are there any prohibitions against terminating a Tray Cable with a twist lock plug? Cord Cap is listed under UL standard 231A. Service is 480V single phase.

Thanks,
 
If you are using tray cable, 336.10 and 392.6 have limitations. including a 6 ft maximum length,
 
augie47 said:
If you are using tray cable, 336.10 and 392.6 have limitations. including a 6 ft maximum length,
Click to expand...

Thanks augie. I've got that part covered and all is well. I just wasn't sure if installing a twist lock was acceptable since I've never done that.
 
eric9822 said:
Are there any prohibitions against terminating a Tray Cable with a twist lock plug? Cord Cap is listed under UL standard 231A. Service is 480V single phase.

Thanks,
Click to expand...

Does not seem right. Tray cable is intended for fixed, permanent installation, does not have the high-strand conductor that is provided in SO and other portable cords that ARE provided with that feature to facilitate frequent removal and movement.
 
weressl said:
Does not seem right. Tray cable is intended for fixed, permanent installation, does not have the high-strand conductor that is provided in SO and other portable cords that ARE provided with that feature to facilitate frequent removal and movement.
Click to expand...
I agree. They are called cord caps for a reason... :happyyes:
 
Thanks for the feedback. This is actually related to another thread I started here http://forums.mikeholt.com/showthread.php?t=151927&highlight= but didn't get a lot of responses.

We have a whole bunch of high bay lights that are hung by 3/4" RGS conduit with a tee and some liquidtite right before the hangar for the branch wiring to exit. Most of the existing lights are hardwired. Since these things are in a false ceiling that can get to over 110 degrees 90% humidity one of our more creative electricians added receptacles at some of the locations and modified a twistlock plug to fit on the end of the liquidtite; I know this is a no-no. This was done over twenty years ago and the purpose was so fixtures could be swapped out fast. Now we want to replace some of them and feed the fixture with Tray Cable and retain the plugs. Excerpt from the UL White Book:
ATTACHMENT PLUGS, FUSELESS (AXUT)
GENERAL

Terminals
? Terminals of appliance couplers, appliance and flatiron
plugs, attachment plugs, cord connectors and table taps are intended for
use with stranded copper conductors of the type used in flexible cord

"Normal" TC-ER cable is out but based on the White Book I would think that flexible TC-ER rated cable like you use for CNC machines and such would be OK. Opinions?


 
eric9822 said:
ATTACHMENT PLUGS, FUSELESS (AXUT)
GENERAL

Terminals
— Terminals of appliance couplers, appliance and flatiron
plugs, attachment plugs, cord connectors and table taps are intended for
use with stranded copper conductors of the type used in flexible cord

"Normal" TC-ER cable is out but based on the White Book I would think that flexible TC-ER rated cable like you use for CNC machines and such would be OK. Opinions?
Click to expand...
As suspected. The wiring must be recognized by the NEC as flexible cord or an equivalent. I've not used and not aware of any TC cable which has the same stranding as flexible cord... uncertain about TC-ER.

The next question would be suitability of the strain relief. Does UL say anything about that?
 
Smart $ said:
As suspected. The wiring must be recognized by the NEC as flexible cord or an equivalent. I've not used and not aware of any TC cable which has the same stranding as flexible cord... uncertain about TC-ER.

The next question would be suitability of the strain relief. Does UL say anything about that?
Click to expand...

The UL white book says nothing about strain relief but we would use CBG's. The Flexible TC rated cable I have used in the past has about the same stranding and flexibility of SO cord. My dilemma:

Terminals
? Terminals of appliance couplers, appliance and flatiron
plugs, attachment plugs, cord connectors and table taps are intended for
use with stranded copper conductors of the type used in flexible cord.

It does not say it has to be flexible cord, it says it has to have the stranded copper conductors of the type used in flexible cord. It would be so much easier if UL and NFPA left less to interpretation.
 
eric9822 said:
...
It does not say it has to be flexible cord, it says it has to have the stranded copper conductors of the type used in flexible cord. It would be so much easier if UL and NFPA left less to interpretation.
Click to expand...
That's why I said...
The wiring must be recognized by the NEC as flexible cord or an equivalent.
Click to expand...

Dual rated, as Jacob posted is the best option... :happyyes:
 
The vendor is claiming the install is allowed because 400.7(A)(2) says flexible cord is permitted for the installation of luminaires. While that is true I don't believe 400.7 supercedes 400.8. I also just found this little gem in the 2011 NEC:

410.62 Cord-Connected Lampholders and Luminaires

(C) Electric Discharge and LED Luminaires

(1) Cord Connected Installation. A luminaire or a listed assembly shall be permitted to be cord connected if the following conditions apply:

(1) The luminaire is located directly below the outlet or busway
(2) The flexible cord meets all the following:
a. Is visible for its entire length outside the luminaire

While we are still on the 2008 the only difference in the section is the addition of LED luminaires so I think the intent is clear.

Thanks for the link Jacob, that should solve the problem. I will share it with the vendor. Again thanks for the responses all.
 
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