Motor Disconnects

[augie47]

Please note that this question is related to equipment installed under the '08 Code as later Codes have some changes:
I have a sandblast machine newly installed in an industrial facility. There are 30 motors associated with this machine. All the motors are controlled from a central motor control
assembly which is equipped with one external disconnect. The individual motor starters are supplied thru individual (one pole) din-rail fuse disconnects within the control cabinet.
The motors do not have individual disconnecting means. The facility is taking the stand that their lock-out/tag-out procedure allows this install.\
As I read 430.102 ('08) the LOTO provision only applies if the controller disconnect means is individually capable of being locked out.
I do not feel this install meets the requirements to allow the absence of individual disconnects in sight from each motor.
Comments ?

 

[kwired]

Was it 05 or 08 when they made changes here? Seems to me it was 05.

Whenever it was it used to be you could have a lockable disconnect at the motor controller location and wouldn't need one at the motor location. But since the change there are very little exceptions that allow that practice to still be done. IIRC the word impracticable is used in there - which itself is subject to interpretation for each and every installation.

One place that does make sense is for a submersible pump motor - where are you going to put a disconnect that is within site of the motor and is accessible in most cases with such an application?

 

[jxofaltrds]

Lines in the picture are mine for other reasons. I make notes in my PDF version.

Once I make notes I can't copy that section of the code. Down side of adding notes.

 

[augie47]

Mike: I am more acquainted with the Section than I want to be
I guess it's in interpretation question. To me individual controllers supplied by a din rail fuse block do not meet the criteria of "individually capable of being locked in the open position" especially since one has to enter the cabinet to open the fuses.
I'm curious if anyone sees it differently.

 

[rbalex]

It is conceivable that their installation meets a combination of [NEC 2008] Section 430.102 (A) Exception no. 2 and 430.102 (B) Exception to (1) and (2) (b); however, depending on horsepower size(s), it seems they could have problems with Sections 430.108, 109 and 110; especially 430.109.

 

[don_resqcapt19]

If this is a machine, does the NEC apply? I have seen a lot of industrial equipment that were built exactly like that. That is a single external disconnect with individual disconnects internal to the control panel for each of the motor controllers.

 

[Strathead]

Mike: I am more acquainted with the Section than I want to be
I guess it's in interpretation question. To me individual controllers supplied by a din rail fuse block do not meet the criteria of "individually capable of being locked in the open position" especially since one has to enter the cabinet to open the fuses.
I'm curious if anyone sees it differently.

I think it would all hinge on the interpretation of "controller". The code section you are referring to states, "the controller disconnecting means" and if the control cabinet that has an overall disconnecting means is the controller, then the code section clearly allows it to act as the disconnect for all of the motors the it feeds, either within site or capable of being locked. Do you have reason to interpret the control cabinet as not being the "controller"?

 

[rbalex]

If this is a machine, does the NEC apply? I have seen a lot of industrial equipment that were built exactly like that. That is a single external disconnect with individual disconnects internal to the control panel for each of the motor controllers.

The question is whether the machine/motors can be worked on safely under administrative controls. The OP gave the impression it was an integrated machine, so it may be beyond the immediate scope of the NEC, but not OSHA. That's why I said it was conceivable. OSHA does accept administrative controls.

For the purposes of [2008] Article 430, controller is defined in Section 430.2.