mdshunk said:
You're under the very mistaken impression that there's some sort of inherent danger in re-installing existing circuit breakers onto a new panelboard bus. You'd be hard pressed to find any documentation to back that up. The existence of a testing procedure is not, in itself, a requirement that such testing even need be performed.
As in my previous post, re-use of small breakers may pose little risk to the end user (home-owner). We've all heard the term "weak-breaker", one that nuisance trips due to heat, or other problems that are site specific. As a GE Field Engineer (one who actually tested breakers and switchgear), I would ask anyone who re-uses breakers if they have kept track of where the devices came from (to the guy with the buckets of fuses and breakers - these devices do have set life-expectancy when they trip and clear faults multiple times, fuses do have burn-in from high inrush currents that are close to the fault clearing value). I would ask, do you know how many times the breaker has cleared or tripped due to a fault?
One impact on a breaker after it clears a fault is the scoring and deteriation of the contacts due to the arc and heat created from the fault. When the contacts come back together for normal service, the surface area is affected, and the breaker may run hot. For small breakers (20A in a residence, this may not present a serious problem). However, say for a 2000A breaker, the contact surface is much larger, heat load is much greater (and generally less diverse). For normal servicing of these size breakers, we perform "conductance" tests to ensure the contacts have a very low resistance (in the micro-Ohms).
I say, use caution when re-using equipment, as you are assuming the liability for its proper operation when doing so.