Corrosion causing breaker to trip?

[ZX12R]

Unknown to me,when it rains hard,water has been leaking down the wall onto a switch in the wall.The switch controls a light that is always on at night.The other day,the breaker trips for the first time.When i inspect the switch,the ground wire is very corroded from the water.Will this trip the breaker or is there a short somewhere else?

[ampz]

The water also probably caused the breaker to trip.Need to find that leak & plug it up.

[ZX12R]

yes,but its been dry for a week,and the breaker just started tripping two days ago so its not the water.

[John Nelson]

Corrosion can cause an open circuit, but I don't see a reasonable way it could cause a short. I'd still bet on the moisture, even after a dry week. I'd be more concerned about mold than electrical problems.

[Cheyenps]

My guess would be moisture in the switch itself, which has corroded internally to the point that it now shorts to the mounting strap. I'd change the switch and see if the problem goes away.

Check for water in the light box as well - pretty common, especially if the light is not coverd by a roof overhang.

[ZX12R]

Thank you for all your replies.I am going to replace the switch to see what happens and I will let you know the results.