Nec 430.245 & 348.30

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beanland

beanland

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Location
Vancouver, WA
We have a chiller, 480V 300A, connected to an enclosure by flex conduit. The flex is about 8 feet long and resting on the concrete floor. The 430.245 handbook note seems to state that for vibrating equipment, a piece of flex not more than 6 feet long is appropriate. But, this is not a case of flex to a motor. This flex in the branch circuit from the fuse enclosure to the motor controller. However, the motor controller is integral with the chiller and subject to vibration. 348.30 for FMC says securely fastened every 5 feet. So, is the correct interpretation that the FMC can be any length as long as secured per 348.30?
 
The 6' limit on the remote motor terminal box is for grounding purposes. FMC needs to be supported 12" from any box or enclosure and 4-1/2' on the run. The exception for the 5' is where the motor frame moves and needs fexibility.I would say you need atleast 3 straps in the 8' run providing you ran an equipment ground.
Rick
 
How long is that going to last laying on the chiller room floor, a couple of

short peices of deep strut would at least keep the water off the FMC. jmo.
 
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