"Why would a contractor put screws through circuits to leave them 'on'? "

No idea, ubnless it was a reminder to the workers to not turn off those circuits.

It will NOT actaully hold the breakers on though.

All breakers are designed to open even if the handle is held on or cannot move.

The handle is actually disconnected from the internal mechanism when the breaker trips.

This is the reason they must be moved fully to off (engages the handle and cocks the spring that forces the breaker open) and then back to the on position to restore power.

We tried and could not move the breakers to 'off' for these two. We are very familiar with how to reset the other breakers from 'off' to 'on' but these two do not move. So it sounds like it is safe for us to remove the screws and switch these off then back on.

I can see why you would put those on the breaker for the refrigerator - but not for an oven. You can just remove them if you don't like them and aren't worried about somebody accidentally turning those circuits off.

Those devices are typically installed to prevent someone from turning off the circuit. They will allow the breaker to trip. Usually only see those in industrial settings where they don't want emergency lights or some other safety system shut off.

You can remove them and leave them off. Loosen the screw and slide them off.

Thank you for the advice. We removed the screws with no problem and reset the appliance and all is well. Great not to have to get the appliance repaired and not have to call in an electrician for this one!

My experience, those are breaker lockoffs. They are intended to be turned around to lock the breaker in the off position when service is being performed on the appliance.
They are typically required by the inspector when the breaker is used as the disconnecting means for an appliance.

Correct, lock-off breakers are just for that. They prevent the breakers from being turned back on, or reset while someone is servicing said equipment. Similar to lock-on/lock-off tags.

For example a range can either be hardwired or plug-in. All electrical equipment has a means of disconnect. In most cases this is accomplished as a plug-in. The plug-in serves as the means of disconnect. When you need to service it, you disconnect it from the power source by pulling the plug out of the receptacle. In a range, if it is hard-wired, the repairman goes to the panel and turns the breaker off. In order to prevent someone from turning the breaker back on while the repairman is servicing it, they engage the lock-off.

Those are not safety lock offs. If they were there would be a place for a pad lock that only the installer has the key for. There would also be a tag with his name etc on it. It prevents anyone from removing it and turning it on while he is working on it.

Those are simply to prevent someone from turning off the breaker to a critical piece of equipment.

joed, go to,
http://ecatalog.squared.com/fulldetail.cfm?partnumber=QO1LO
It shows the Square D style of the same thing. They are sold as breaker lockoff devices. Not Lock Out Tag out safety devices. I was not able to locate the ITE brand but you can easily tell that they are similar.
And yes they can also be used to lock the breaker in the on position.

I was responding to this quote. They are not designed for safety while servicing the equipment.

Correct, lock-off breakers are just for that. They prevent the breakers from being turned back on, or reset while someone is servicing said equipment.