What is the 42 circuit rule for panelboards?

Issue:
Information on 42-circuit rule for panelboards.
 
Product Line:
Panelboards
 
Environment:
NQ, NF, I-Line Panelboard
 
Resolution:
Not more than 42 overcurrent devices (other than those provided for in the mains) of a LIGHTING AND APPLIANCE branch-circuit panelboard shall be installed in any one cabinet or cutout box. (NEC, Article 384-15)

A LIGHTING AND APPLIANCE branch circuit panelboard is one having more than 10 percent of its overcurrent devices protecting lighting and appliance branch circuits. A lighting and appliance branch circuit is a branch circuit that has a connection to the neutral of the panelboard and that has overcurrent protection of 30 amperes or less in one or more conductors. (NEC, Article 384-14)