Support for greenfield/FMC

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bnbowen@uiuc.edu

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If I understand article 348.30 and it's exceptions correctly...... as an example, 1 inch greenfield can be as long as necessary,(if supported every 4.5 feet and 12 inches from each end) but if it is used for flexibility it can only be 3 feet long and supported 12 inches from each end. Is this correct? A contractor dropped EMT from the ceiling to a junction box and then ran 3 feet of greenfield to the connection box of a motor. The greenfield had a 12 inch clip connected to the JB (factory made). Should the greenfield be supported at the motor per 348.30,(A) and if so how? Thanks for your help, Brad
 
bnbowen@uiuc.edu said:
... but if it is used for flexibility it can only be 3 feet long and supported 12 inches from each end. Is this correct?
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No.

It can still be longer than 3'. The 3' in the exception is the maximum allowable unsecured distance at the terminus, contrasting 12" in the general requirement.
 
Not arguing, just trying to understand

Not arguing, just trying to understand

Understood that it can be longer than 3 feet but it seems to me if you need flexibility, the 4.5 foot rule would be better for motor vibtration than 3 feet. Any thoughts? Is there a means of support for greenfield entering the top of the motor connection box? Thanks again, Brad
 
ActionDave said:
The 4.5 distance for securing shrinks to twelve inches at a termination unless you need it for flexibility at the motor.

Don't think of it as losing 1.5 feet of flexibility, think of it as gaining two extra feet after the last strap.
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Well said. :)
 
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