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I am not certain the NEC states this however the motor installation may require flexibility in which case it may not be hard wired.
 
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Electric Al
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Dennis ! On post #3 I realize that when you say hard wired , you mean hard Piped .

Just thought I would bring this to your attention before someone jumps on it !
 

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Dennis ! On post #3 I realize that when you say hard wired , you mean hard Piped .

Just thought I would bring this to your attention before someone jumps on it !
TY-- yes I meant hard piped...:thumbsup:
 

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I don't think it does, but the other side of the coin is, just because the code does not expressly prohibit something, doesn't automatically make it good practice.

The majority of industrial sites I work at would prohibit such a practice and I would think twice about what the perceived benefit would be.

The other hint is 430.223 "Raceway Connection to Motors". They make a point of allowing a flexible connection from a raceway to a motor. Yes they just allow it, not require it.

At any rate, even if the motor is rigidly mounted I'd consider at least just using MC. Makes it much easier to replace, and all motors vibrate a little.
 

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I don't think it does, but the other side of the coin is, just because the code does not expressly prohibit something, doesn't automatically make it good practice.

The majority of industrial sites I work at would prohibit such a practice and I would think twice about what the perceived benefit would be.

The other hint is 430.223 "Raceway Connection to Motors". They make a point of allowing a flexible connection from a raceway to a motor. Yes they just allow it, not require it.

At any rate, even if the motor is rigidly mounted I'd consider at least just using MC. Makes it much easier to replace, and all motors vibrate a little.
I agree with what you say.

Pete
 

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Donuts > Fried Eggs
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I think we really use it because it is much quicker and easier than trying to hard pipe the motor.
I don't find anything faster or easier about installing a flexible whip on a pipe run as opposed to landing that same pipe directly at the device. Takes extra labor to make up the whip, and often extra time to get the conductors through it.
 

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We have a few places with motors that are piped with RMC. Real pain when you go to replace one because the pipe is always in just the right spot that it's in the way of lifting/shoving/prying the new motor in place.
 

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I think the value of flex is often really overrated, and we use it mostly because that's the way it's always been done.
If it's really that tough to pull te cables through 6 feet of sealtite and put 2 connectors on, then I'd consider that the value of MC cable in such a situation is really underrated, and makes the whole question a non-issue.

Besides the fact that, like JLarson said, if we went into an industrial site and hard-piped right to motors the maintenance department would be chasing us with torches and pitchforks. :)
 

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Big John said:
I think the value of flex is often really overrated, and we use it mostly because that's the way it's always been done.
Agreed. That being said, even I've never hard piped a motor. Yet
 

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Running pipe to a motor is the most chicken**** thing i have ever heard of, we have hundreds of motors in our plant, some on equipment that was put together before it came in, anything that does not have cord or SO is LFMC, period, no rigid, EMT, flex, mc, etc. Anybody likes pipe that much is a wanna be plumber or needs to come out of the closet.
 

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The only time I've ever hard piped a large motor is when the whole unit is sitting on an anti-shock base. Even then you flex into the unit..
 

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I don't find anything faster or easier about installing a flexible whip on a pipe run as opposed to landing that same pipe directly at the device. Takes extra labor to make up the whip, and often extra time to get the conductors through it.
In my area they want the motor terminal box opening on the bottom side of the terminal box. Hard pipe would almost always require an additional conduit fitting or two, and an union (most all of the motor terminal boxes that I see have a threaded opening). Conduit labor is always greater than flex labor. The conduit fittings and union will cost more than the LFMC and two connectors.

Our installations almost always have the control conductors for the HOA in the same raceway as the motor conductors and the wire will be pulled to the Tee fitting where the wiring will be split between the motor and the HOA, and not directly to the motor, so no additional wire pulling labor.
 

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Donuts > Fried Eggs
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I have always used flex, but either way, your looking at at locknut holding it together
13,000 horsepower, 4" rigid:



I agree with y'all that flex can definitely make changing a motor easier, but I've also swapped a lot of hard pipe with little trouble. I see a ton of hard pipe on large frame motors where a couple feet of flex wouldn't make a bit of difference in the overall difficulty of removing it.

I guess my point is to actually think about the install instead of doing it "just because": If hard pipe isn't gonna screw future maintenance and it makes my job easier, you bet I hard pipe. But if maintenance or vibration/sound calls for flex, so be it.
 
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