Simple switch...not simple problem

I have a basic light switch that is not at the end of the circuit. Using two wire Romex with ground. I have the two white wires connected to each other. I have both ground wires connected to the green screw on the switch. I have one black wire on the silver screw and the other on the brass screw on the switch. When I test the power by turning the breaker on before putting everything back in the wall it works fine. I put in back in the wall and once the switch is on for 10-15 seconds it pops. Light bulb is still good.....circuit breaker doesn't blow. I am not an electrician but have wired dozens of switches. Am I losing my mind or have I missed something?

 

I would make sure you don't have bare wires touching or the sides of the switch touching the enclosure when you button things up. If that doesn't do it I would replace the switch with a new one.

 

An ordinary switch has tow brass screws. What kind of switch is it?

 

Yup....checked that the second time it happened. Thanks!

 

Don't remember the brand but it's just a single pole, white rocker switch

 

If the circuit breaker doesn't "blow" ..... what is popping ?
You either have power to that switch or you don't.