Let me think about for a little while and I'm sure I can come up with a reason frogs will still bump their butts even if they had wings.I disagree. Maybe not the best "interlock", but if the 30 amp is supplying the air handler of an HVAC system, and the 60 amp is supplying the compressor, tripping the 30 amp would make it prudent to kill the compressor, too. Otherwise, the coils in the air handler may freeze and burst. If the 60 trips, shutting down the air handler makes the failure obvious to the humans involved.
