Can a circuit breaker be used as an on off switch?

Only if it is listed and rated as such. It will have SW on the label. Otherwise, no. Some circuit breakers are "switch rated," but most are not. Opening and closing a non switch rated circuit breaker will damage the contacts over time. It would be better to have an electrician install a switch. With all the wrong answers, it is easy to see why I say never take electrical advise from the untrained and unqualified people on yahoo.

You need to install a switch rated circuit breaker. They are made to be used a switches, if you use a regular breaker it will wear out. Nec code states that switch duty breakers must be used when they are the means of turning on and off lights, etc.

A breaker is not like a switch and even though you could use it like a switch, every time you trip the breaker, it gets weaker. Eventually it will be tripping by itself with less than the amperage for which it is rated. Its easier to install a switch by the panel and then run the feed from the panel to the switch. Cheaper in the long run too

You can. It's not that big of a deal. It's probably more of a pain that anything. Most restaurants and food chains are set up that way. Even workshop and warehouses are like that. And actually they can last just as long as switches. I've seen 20yr old breaker/switches is some restaurants. Don't sweat it. Now go get me a beer.

I don't know what your application is but yes..they can be used for a switch..I have a large air compressor in my shop & when I leave for the day..I throw the breaker switch

A breaker marked "HACR" can be used as a switch. If it doesn't have this marking, it cannot. They will wear out quicker when used as an everyday switch.

yes,but a special rating "swd" not hacr should be used for

repetative switching (more than once or twice a day).

It'll wear out faster than a regular switch and be much more expensive to replace, since you'd want a pro to do it.

yes that is kind of a pain in the a s s way don't you think? is there something wrong with the actual switch?

Their not made to be used that way and would wear out soon and break inside!