SOOW CORD

[ptonsparky]

Now is a fine time to look at Art 400. Well into the project. Customer with cord suspended from the ceiling feeding equipment on wheels that can or has in the past been moved or rearranged several times a year. Looking at using the same method over again. 6/4 SOOW about 20' lengths via kellem grips and j box at ceiling. Connection to equipment at ground level is via a twist lock that seems to be standard issue for this industry. I am starting to have second thoughts about this method. Some of the equipment does move several feet while in operation, but not all of it.

 

[petersonra]

are you suggesting you think it is not appropriate to use cords to conenct the equipment?

how would one be able to move it otherwise?

 

[renosteinke]

It is perfectly proper to have 'cord drops.'

Having observed both cord drops and dropped pipe, I have to say that the cords performed much better over time. The pipe always seems to get damaged and knocked loose, as well as posing a hazard to personell. The cords, by comparison, can 'go with the flow.'

My one concern, since you mention #6 wire, is your means of disconnection. I doubt the plugs are rated for the horsepower involved, so you'll probably want a switch on the wall nearby.

 

[Ponchik]

My one concern, since you mention #6 wire, is your means of disconnection. I doubt the plugs are rated for the horsepower involved, so you'll probably want a switch on the wall nearby.

What if the OCPD is lockable? You still need a local disconnect?

 

[renosteinke]

Maybe, and maybe not. The devil is in the details, and we're getting into design. While 'good design' almostalways meets code, the opposite is not true. You might take a moment to review Article 90; the NEC is not a design manual.

I just don't want something bad to happen when the motor locks up and someone tries to unplug it. I want the 'off' means to be both convenient to the guy running the machine and nearby. Finally, I want a means to disconnect, and lock out, ONLY that machine.

Somehow, just having the guy go three floors down and put a padlock on the breaker for the entire line just doesn't seem a good way to do things.

 

[petersonra]

Maybe, and maybe not. The devil is in the details, and we're getting into design. While 'good design' almostalways meets code, the opposite is not true. You might take a moment to review Article 90; the NEC is not a design manual.

I just don't want something bad to happen when the motor locks up and someone tries to unplug it. I want the 'off' means to be both convenient to the guy running the machine and nearby. Finally, I want a means to disconnect, and lock out, ONLY that machine.

Somehow, just having the guy go three floors down and put a padlock on the breaker for the entire line just doesn't seem a good way to do things.

i think you are mistaking the estop function for the disconnect function. they are sperate functions and should be seperate devices.

 

[kwired]

It is perfectly proper to have 'cord drops.'

Having observed both cord drops and dropped pipe, I have to say that the cords performed much better over time. The pipe always seems to get damaged and knocked loose, as well as posing a hazard to personell. The cords, by comparison, can 'go with the flow.'

My one concern, since you mention #6 wire, is your means of disconnection. I doubt the plugs are rated for the horsepower involved, so you'll probably want a switch on the wall nearby.

How do you make users turn off the switch instead of pulling the plug? Production employees don't think the same way as maintenance or installers. You can think you have it all figured out and come back later and they are not taking advantage of any features you may have designed. If you have hand/off/auto switches for equipment they will always run them in the hand postion, even though running in auto allows for interlocking machines that should not run if another one stops. Then they act dumb when there is a breakdown and because they were running in "hand" instead of "auto" they caused other complications.

 

[ptonsparky]

Is the cord drop considered a pendant?

These machines all have disconnecting means built into their control panels. For the most part built by a mfg. Control stops are used by production employees. Maintenance personnel? No bets on any single method.

 

[ptonsparky]

The cord connectors are non NEMA configurations that most likely would not meet a HP rating although I have been surprised with ratings in the past.

 

[renosteinke]

Yes, a cord drop is a pendant. What else could it be?

A plug need not be a NEMA pattern; indeed, I suspect you won't encounter any horsepower ratings issues with Amphenol plugs. Some plugs even have a switch built within them, and disconnect the power before you can remove the plug.

Another matter is LOTO, and you'll have to look to your plant's practices to answer that one.

I mentioned the disconnection issue simply because I have no idea as to the specific application, and there are so many different 'correct' answers to this sort of general question.

You mentioned SOOW cord, and I'm sure it's appropriate for you. Still, it needs to be mentioned that there are different types of cords, and whatever cord is used, it must be appropriate for the use.