Adding a local disconnect for a 480V motor

[justfreeze]

Background: An existing 480V power cable is already connected to a 50HP motor. Currently this 50HP motor is locked out at the starter. A request was made to install a local disconnect for this motor but around 100' away from the motor. The decision was to run a new cable directly to the new local disconnect from the starter and then downstream of the local disconnect to the 50HP motor.

My question: Why couldn't they just put a junction box where the existing motor cable is then run the new cable down to the disconnect and then back up to the motor since this is a shorter distance then running new? I have limited expereience regarding this, is it because it is not to code to install a junction box out in the field for 480V? If this is so can someone point me in the right direction regarding the article in NEC so I can read up on it?

 

[augie47]

Sorry I can't follow the thread, but you might want to look at 430.102(B).; With limited exceptions, a motor must have a disconnect "in sight from" which is limited to 50 ft.

 

[petersonra]

Why couldn't they just put a junction box where the existing motor cable is then run the new cable down to the disconnect and then back up to the motor since this is a shorter distance then running new?

I can't think of any code requirement that would prohibit doing so.

As another poster mentioned though, the requirement is generally that you have the disconnect within 50 feet, but with some pretty wide exceptions.