The subject of cords came up in another thread, so as long as cords are a topic as of late..........
How do you guys feel about the practice of hooking up machinery in industrial settings with cords drop from the overhead? For a hypothetical instance a machine bolted to the floor, say 10 feet long, leveled to within thousandths of an inch, maybe 5 or 10 horsepower. It's never intended to be moved. A connector body on the end of a cord that drops from a box above, and a cord and plug are field connected on the machine.
What are your thoughts?
[This message has been edited by electure (edited 09-25-2006).]
First of all, anything that gets the wiring out of the way gets my vote. I've seen way too much damage from trips, getting bumped into, etc.
Even when the machine is never going to be moved, is absolutely without vibration, etc... quite often covers are removed, raw material is transported, etc. A cord has some "give," and a plug will come out before damage occurs (usually). Much preferablt to having a poor forklift maneuver result in sparking, non-continuous pipe.
There is also the issue that pipe that drops down from a 20 ft ceiling is in no way properly supported- not in my book. And my supplier is fresh out of skyhooks. I'd rather see a properly strain-relieved length of S drop directly to the machine.
Agree with John 100%. Spent a lot of time when I first got into the trade in a very large machine shop. We used mostly SJ drops due to machines getting moved even when they were supposed to be permament and saw a lot of conduit damage from fork lifts ETC. The SJ being flexable held up better. We'd pipe to directly over the machine, add a box and then make an SJ drop.
What bothers me was seeing SJ tie wrapped to trusses and in places down low subject to physical damage.