ThinkGood,
I am not thoroughly familiar with that particular model of breaker, however all the breakers I am familiar with will trip with the “handle” resting in the middle position. This trip or “opening” (electrical tech talk) of the breaker could have been caused by an overload, as in plugging in too much stuff(load) or alternatively, a fault condition (short circuit in some stuff plugged into the branch circuit). The fault or short circuit condition could also have occurred in the branch circuit wiring itself rather than utilization equipment (some stuff) plugged into the branch circuit. There is no way of knowing by looking at the tripped breaker. If the breaker is closed (reset) into a fault there is a possibility of an arc flash. Still best to stand off to the side of the panel and turn / look away when resetting a breaker. Also a good safe work practice would be not to wear synthetic or synthetic blend clothing such as, poly blend shirts, nylon windbreaker jackets etc. when doing this operation. Wanna be extra safe also wear heavy cotton or leather gloves. It’s not really overkill it kind of like wearing the right clothing if you are welding underneath your car, or sandblasting, safety glasses ehen using a chain saw etc, etc, or anything which requires the right clothing AKA, PPE personal protective equipment).
When it comes to the wearing of PPE, remember. You can't win, you can only loose or break even! You go to work with two eyes, two hands, two legs, ten digits etc. You won't ever return home with more only the same or --if you loose, you'll return home with less.
OSHA Professor
