If one machine is going to control another machine you have to do it in the control panels.
If you mean an aux contact on the 600V machine starter.The starter would then be fed from two sources and have to be labeled as such.You could also do it with an 8 pin relay.
It seems that when a panel/tub is fed from two sources inspection wants any circuit that cant be turned off at that panel to be extra-low voltage.
This is how JOHNSON CONTROLS and TRANE wire METASYS and TRACER SUMMIT for building automation.An aux contact could utilize the starters own control circuit to control the relay provided its 120v.This way the entire starter assembly will still denergize with the disconnect should someone have to pull it apart for maintenance plus keeps everything as physically seperate as possible.Need more information.
[This message has been edited by frank (edited 01-23-2007).]