Molded case circuit breaker mechanical rating plug
 A molded case circuit breaker having a thermal-magnetic trip unit is provided with a mechanical rating plug to allow a number of circuit breakers of different ampere ratings to be used within a common-sized enclosure. Multiple mechanical rating plugs are stored at the place of distribution to adapt the common enclosure to a specific ampere rating at a substantial savings in time, labor and materials. 
General Electric Company
H H
H01H H01H
additional inventional
David Roger N.
Arnold Castonguay