I just wanted to mention that I recently heard that Murray has somehow redesigned their Panelboards and claim that other breakers tested and classified for use in the older panels can not be used in newer Murray Panels.
This is a very interesting situation. I myself am a little confused over this issue, because of conflicting info that is available. I have some info in my office, I am at home, that I will dig up later about this. I will say that I have spoke to both UL and individual manufacturers about this subject and I cannot do justice to this subject until I get the info from my office.
Bill, If Murray has redesigned the bus in their panels, then neither the listed nor classified breakers made for the older panels would be permitted to be used in the new panel. If they made a big enough change to be able to patent the new bus and breaker design, they will be able to prevent any one from making "classified" breakers that fit the new panel. I believe this is exactly what happened with the Square D QO breakers. That bus design is unique and was patented by Square D. There were no third party breakers available for that panel for many years. Now there are "classified" breakers that can be used in the Square D QO panels. I assume that this is because the patent has expired. Don
This issue of "classified breakers" is one of the reasons that I believe that 110.3(B) only applies to the information in the actual "listing and labeling" and does not include "manufacturer's instructions" as all manufacturers state that you can only use their breakers in their panels> Don
All of the breaker manufactures have published statements like that. Yes, they may be able to void the warranty, but that does not make the use of "classified" breakers a code violation. The "warranty" issue is a legal one, but I have been told that it can be voided if a contractor installs the classified breaker, but not if the end user of the panel installs the "classified" breaker. (is our resident attorney still around?) This is a perfect example of a "manufacturer's instruction" that 110.3(B) does not require you to follow. Don