^{Residential, commercial 
and industrial series ratings}

• E7819 Spreadsheet, UL Listed Series Rating Combinations
• BR loadcenter series ratings
• CH loadcenter series ratings
• Panelboard & switchboard series rating information manual
  (Yellow Book)
  

^{Metering, loadcenters
and panelboard product information}

• Metering, loadcenters and circuit breakers catalogs
• Industrial circuit breakers
• Panelboard products

See the generic example. The “Main” Overcurrent Protective Devices (OCPD) within a power distribution system, will have a marked interrupting rating equal to, or greater than, the available fault current (AFC). However, an additional “branch” circuit breaker may be connected on the load side of the OCPD, with a lower marked interrupting rating, as long as the Main and Branch combination of breakers can safely interrupt the AFC, and are listed by UL.

Combinations that satisfy these requirements can be found in the metering and loadcenters catalogs or the panelboard and switchboard manual.

• The circuit will be interrupted safely at least once
  
• Lower cost when comparing to fully rated devices and selectively coordinated devices

• Main or branch breaker, or both may need to be replaced
  
• Either one of the breaker on the system could trip, the system is not designed to selectively trip

• Locations where continuous power is not as critical (residential, certain factories, etc)