I've been looking for a light switch like this. It alerts me when the light is on in the garage. Anyone know where i might find one? One toggle operates the den overhead light and the other the garage overhead.

I have a 30 amp double pole breaker in my main panel that feeds a sub-panel for the pool equipment. A days ago, I noticed the pool pump was not on. Tracked it back to a tripped 30 amp DP supplying power to the pool sub-panel. Turn off the breakers on the sub-panel and 30amp DP breaker in the main still trips after a few seconds of being reset. After a time or two of testing this, the 200amp Service Disconnect tripped. Since there was no power being drawn by the pool equipment (breakers at the sub all off), I replaced the DP 30amp breaker in the main panel to see if that was the problem, but got the same results. I next disconnected the wires feeding the sub panel (at the sub-panel) and capped them, reset the breaker and again trips after a few seconds. This was leading me to believe there may be a short in the wires between the Main and Sub panel, but I am looking to see if there are any other possible culprits before pulling new wire to the pool sub-panel. I also disconnected the wires from the Main panel, capped them and used an Ohm meter (from sub-panel side) to test the 4 wires (each to each other) for any shorts with no results. Any thoughts on next steps or possible issues here? Any other test on the wires I can run before replacing them? Any other possible issues at the main panel? The run to from the main to the pool panel is about 20 years old and has been working until recently. Its about 60' liner distance between panels. No new work was performed in the sub-panel or main-panel in the last 9 to 12 months, and no recent digging near the conduit. This is a Square D Homeline main panel/breakers.