ECN Forum Forums Code Related Discussion NEC & other Code issues Cord Drops

Greg:
As I said above, that equip has to be 'moved' to clean. Falls under Health Dept.
Same in FDA regulated mfg.

John

JBD:
"Pendant" is not in Article 100 defs.
To the best of my knowledge, it has to 'hang', like the control station for an OH crane.

John

I've wondered about the pendant thing for a long time (maybe 30 yrs). All I've ever been able to find has been references to pendant lighting, and like John says, crane controls.
Then you have Daniel Woodhead's products, clearly advertised as pendants.
I sure don't see how something secured at the bottom could be considered a pendant.

314.23(H)(2) makes reference to enclosure on conduit pendants that are not supported by other means. Does this mean that "pendants" can be supported on both ends?

JBD:
Your above reference deals with requiring a means of movement on a stem of conduit to prevent damage. Basically, a stem mounted exit unit in a whse that could be hit by a forklift.

I guess you could call that a 'pendant' as I called it a stem.

314.23 (h) (1) addresses cord pendant boxes.

John

Electure:
Ah, Daniel Woodhead, a pleasant memory.

Havn't seen any of them around here for quite some time.

As I said, this is a much debated subject (cords)

John

Just to throw another log on the fire:

What is the basis for the prohibition against using flexible cords as building wiring?

Clearly there are good historic reasons for doing so; cloth covered rubber insulated wires bundled in a cord have no comparison to conductors protected in raceway, or physically separated as in knob and tube.

But compare modern flexible cords to, for example, modern non-metallic cable types. The flexible cord has thicker insulation, and more finely stranded conductors. The insulation material is different, but has similar temperature rating. The insulation is softer, and probably more prone to damage, but the sheath is much thicker, and can 'absorb' small nicks and tears without exposing the inner conductors.

I see no reason _in principal_ that flexible cords could not be safe for permanent installation as building wiring. The cords would need to be suitably tested and listed for long term hidden stationary use as well as flexible use, so not all cord insulation would be suitable. The cords would probably need different support means, different clamps at junction boxes, and possibly different termination techniques to use with the finely stranded wire. The conductors would need to be sized to article 310 rather than article 400, and there are probably a number of other issues.

I bet that there are situations where it would be quite useful to have 'dual rated' cable that was both one of the 'SO' family of cords, and _also_ listed as a type NM cable.

-Jon

Jon, I'll see your bet and raise you one.

I can't think of anyplace it would be advantageous at all.

Just a personal observation, but most of the places I've seen rotten cord has been where it's NOT been flexed, has been in a stationery position for years, and when someone goes to flex it, the insulation crumbles off of the individual conductors.
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On different notes, pendant comes from the same word as pendulum, appendage, etc., which are free to swing, & attached on one end.
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(BTW) 400.8(7) Was added in the 2005 NEC to include "where subject to physical damage" as a use not permitted. The "better because it gives some if hit" argument is no good. Could this be just the reason it was added? to clarify the intent?

Electure:
You're bring back more now vivid memories.....

The petrified SO/SJ twirled around the jack chain, from the 3"round box, down to the 2-lamp40 industrial. 30 years, in place, serving the <100 watt load, exposed for all to see.

Or, how about the plastic item that provided 3 places to plug-in a 2 wire lamp cord, that was "wired' onto the baseboards? Heck, they even made them that you could 'feed thru' & go all the way around the room. That fine 18/2 zip cord, extending the sole 'receptacle' in the room to two or three other places. On a good day, you could feel the heat.

Of course, the zip cord was protected by the 30 amp edison fuse.

John

I also agree with John and Scott.

The majority of times I find rubber cords damaged is when they have been used ion permanent non moving installations.

I think it is similar to dry rot, it becomes brittle it cracks and will start flaking off.

[This message has been edited by iwire (edited 10-06-2006).]