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Does a pendant drop required a plug at either end?

Does a pendant drop required a plug at either end?

New postby JohnSTI on Tue Aug 30, 2016 2:23 pm

I have several CNC Machines at my facility that looks like Pendant drops were going to be used but someone decided to hard wire the flex cord at each end. Is this a violation?
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Re: Does a pendant drop required a plug at either end?

New postby Jerry Peck - Codeman on Tue Aug 30, 2016 4:57 pm

Is that a disconnect switch in that box up on the rafter/beam? The disconnect should be down near the equipment too.

From what your photo is showing, my answer would be: No, that is not a permitted use under 400.8 Uses Not Permitted and 400.7 Uses Permitted of the NEC.

If the drop from the box at the beam was in raceway down to a box on the wall near the equipment, the disconnect located at that lower box, and flexible cord run between a box which is now lower and closer to the equipment and to the equipment itself, my answer would be "depends" ... as it would depend on if the equipment meets the allowances permitted in 400.7 Uses Permitted and not under 400.8 Uses Not Permitted.

Currently it does not meet 400.7 Uses Permitted: (1), (2), (3), (4), (5), (6), (8), (9), (10), or (11).
- It might meet 400.7 Uses Permitted (7), but that is not shown in the photo either way - you would need to determine that on-site.

Currently it seems to fall under 400.8 Uses Not Permitted as it meets; (1), (4), and possibly (7) ... unless it meets 400.7(7) based on 400.8 stating "Unless specifically permitted in 400.7, flexible cords and cables shall not be used for the following:"

Unless that cord, installed from a lower junction box and then run as a shorter piece to the equipment, meets 400.7(7) "Prevention of the transmission of noise or vibration.", then it would be 400.8 Uses Not Permitted.

HOWEVER, as currently installed hanging from the rafter/beam, even if it was installed to meet 400.7(7) for transmission of noise or vibration, it still meets 400.8 Uses Not Permitted because it is being used "(1) As a substitute for the fixed wiring of a structure."

2014 NEC 400.7 & .8 flexible cord uses.jpg
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Re: Does a pendant drop required a plug at either end?

New postby JohnSTI on Wed Aug 31, 2016 7:06 am

Jerry the box up top in the rafters is only a junction box. There is no disconnect switch except the one located on the CNC machine it's self. The only other is the breaker located in the panel box where the conduit run in the rafters originates from. I included another picture that give you a slightly closer look but is the same kind of connection as in the original post, but from a different CNC machine. The connection in this photo though happens to be utilizing a strain relief connector into the junction box. The origin photo from the first post seemed to be using a compression type connector at the junction box but has a tension strain relief located about 6ft away from the junction box. You mention that the flex cord may be in violation of 400.8(4) is this because of the tension strain relief from the original post photo?...

* So the Flex cord doesn't meet 400.7(1) as a pendant drop? why the lack of a plug?
* The conduit and junction box in the rafters was run the same time as the flex cord for the purpose of powering the CNC so it wouldn't fall under 400.7(11)
becasue the junction box isn't an electrical outlet and wasn't per-existing?
* I 'm sure the flex cords wasn't used for 400.7(7) because other CNC have pendants drops (flex cord) have a plug/receptacle connection at the CNC (not
hardwired) like some others, but that's not to say that particular machines are more sensitive than others.

Thanks
Jerry

I'm absorbing your knowledge....keep it coming....lol
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Re: Does a pendant drop required a plug at either end?

New postby Jerry Peck - Codeman on Wed Aug 31, 2016 11:38 am

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