What kind of panel box do you have?

[APW]

Do you have bolt in breakers or snap in?

 

[WikiWash]

I know that commercial properties should have bolt on breakers. My Square D panels do.

 

[MEP001]

It's usually bolt-in breakers for over 100 amps, like the main kill at the top of a breaker panel.

 

[wash4me]

Bolt in copper buss is best followed by bolt in aluminum buss then stab in copper buss and the most common and most likely to fail.....Aluminum stab in!

 

[mjwalsh]

Here is some discussion: http://www.eng-tips.com/viewthread.cfm?qid=386157

 

[sparkey]

You will find in many instances that the snap in circuit breakers will fit in the screw in type circuit breaker boxes. I know the square D QD type breakers will for an example.

 

[WikiWash]

I know that commercial properties should have bolt on breakers. My Square D panels do.

All my breakers are bolt on from 20 amp to 80 amps. They provide a much more secure connection than the push ins.