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

Please excuse my ignorance, but I thought the NEC applied to the building wiring?

If we have a "plain vanilla" industrial rental unit, and I install a Bridgeport vertical mill, does the NEC care whether I use a properly sized and installed cord drop or EMT? Personally, I have been involved with enough remodels and moves to realize that nothing, including the building, is permanently installed.

Seperately, do you have to use the designed "Drop cable" with the multiple bundles of ground wires or could any service cable rated cable (SO, SJO, SOOW, etc.) be used?




[This message has been edited by LarryC (edited 09-25-2006).]

OK, I still stand by Article 400 and the previous comments.

YES, I used to install "cord drops", as everyone else probably has over the past 30 years; BUT not anymore.

Cord has it's place, twistlock at ceiling, for a male t/l on a cord (1-piece) directly to the device is acceptable, IMHO

John

PS: As we said, this is a big debatable subject

Most anything can be misused. The lazy, ill equipped, and incompetent are also quite clever in justifying their actions.

I don't like square boxes with double duplexes hanging from cords. I surely don't like cords looping over the equipment, through the lights, and across the machinery. And, even a proper cord drop that is directly connected to the machine causes me concern.

As I see it, a cord drop ought to drop straight down and end at a cord cap, for a single plug, with very few exceptions. If it's there for general convenience, it probably ought to come from a retracting reel.

We have to protect our stuff from mechanical damage. HOW we do that is a design issue. I agree that a 'hard-wired' cord offers no advantage over flex or EMT.
Yet, this forum has several pics of damaged pipe, even RMC. Cord and plug connections can be a better solution, 'giving' rather than 'breaking.'

I disagree about the plug belonging on the ceiling, though. Usually that is out of reach- so much for a disconnect meand. The entire weight of the cord is held by the plug- and a twist-lock isn't so likely to pull free when you want. I prefer the cord to end at a cap (female plug) just above head level, in a straight blade pattern.

As for "immobile" equipment, it is surprising just how often those machines have major parts (like dies) removed for product runs. Cranes, forks, hoists.... swinging panels, etc.... sometimes that ever-loving drop can't avoid being in the way.

I call it a design issue.

I've found that generally the same people that tout the "quality" benefits of cord drops seem to switch to conduit drops as soon as they reach the "magic" 30Amp limit of inexpensive connector bodies. Larger than that, cord,plug,& connector assemblies cost $$.
I guess larger machines don't vibrate or something
Sure does reinforce the idea to me that they are done because they're cheap and easy.

Like Hotline, YES I've put them in, and sure, there are some applications where they really belong. That's why the NEC allows them under the limited circumstances it does.

Larry C, once the cord is attached to the building, it is a part of the building wiring, just the same as a piece of conduit would be, and yes, the NEC does care.

Reno:
When you put a female cap on the end of a cord, it then becomes an extension cord, no??

Or, you start at a box, hard wire cord from that box, & put a female cap on the other end; that's using cord for permanent wiring??

Cord cannot be used for permanent wiring.

Some of US may not like or agree with Article 400, but, like I tell EC's; it's the Code, I didn't write it, I have to enforce it.

John

[This message has been edited by HotLine1 (edited 09-26-2006).]

How about this
210.50 General.
Receptacle outlets shall be installed as specified in 210.52 through 210.63.
(A) Cord Pendants. A cord connector that is supplied by a permanently connected cord pendant shall be considered a receptacle outlet.

Why can't a receptacle outlet serve a fixed in place machine?

Hot Line, you are correct...as is Electure... when you say that cords are not to be a substitute for proper methods.

Yet, cord does have a place in permanent wiring. Sometimes the reasons may not be immediately obvious though, so I would not want to be hasty in saying something was "wrong".

I suppose ther are two points to consider:

First, we are hired for our judgement, as much as anything else. Then, in order for our judgement to be any good, we need to know the nature of the place, as well as the "nameplate" information.

[This message has been edited by renosteinke (edited 09-27-2006).]

Gentlemen:
As I said above, this is and will remain a much debated item.

Yes, judgement has to come into the decisions, by ALL parties.

Also, a 4x4 box with a duplex recept does not qualify as a pendant.

John

How about a 4x4 box with two duplex recepts? Those are very common in labs and cleanrooms around here.

[This message has been edited by SolarPowered (edited 09-27-2006).]

A pendant box on a cord must have thread hubs, 314.23(H)(1).

If flexible cord pendants are so bad why do so many places in the code allow them?
210.50(A)
314.23(H)(1)
314.25(C)
336.10(7)
368.56(B)
400.7(A)(1)
400.8(4) exception

This discussion sounds too much like "I don't want to see it done that way, so I will look only at my favorite article and not the entire code book".