Using a 3 way switch used instead of single pole.. oops.
A 3 way switch will work perfectly well as a "regular" switch with the third terminal (not the dark, or common, terminal) left empty.
Depending on which wire including the ground is put on which terminal of the 3 way switch, the results would vary from a breaker trip every time, to the situation you described, to completely normal operation.
If you get a breaker trip when you flip a switch, some deterioration of the switch has taken place. After you correct the problem, the switch might last for several more years but you should at least not puzzle over why if it did not.
The more slowly you flip a switch to turn off the light (excluding switches with a built in mechanical snap action) the longer lasting an arc between the opening contacts inside will be. In turn the switch will wear out more quickly. It is possible that the breaker tripping had nothing to do with the ground wire being on one terminal. A breaker with an arc fault circuit interrupter inside may trip with an ordinary light turn off where you moved the switch toggle too slowly.
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Last edited by AllanJ; 11-16-2012 at 08:13 AM.