What screw/bolt through external electrical boxes

[Mike Heidrick]

Any recomendations to a good screw or bolt to use to mount my exterior electrical boxes to my buildings? Was thinking 3" stainless. Any recomendations?

[Dan Hintz]

Just for clarification, you're not suggesting driving a screw through the box itself (from inside to outside), are you? If so, that's a bad idea...

Personally, I would use properly coated deck screws if you're attaching to wood...

[Ole Anderson]

Long term, stainless screws will cause the aluminum to corrode at the point of contact due to galvanic action as they are dissimiliar metals. As Dan said, coated deck screws, even galvanized, would be a better choice. If you use stainless, use a nylon washer to prevent metal to metal contact.

[Mike Heidrick]

Through the holes on the inside of the box (the ones made for mounting screws) into the building Dan.

I will look into galvanized.