CSLB C-10 Electrical ContractorEquipment and InstallationEasy
An electrician installs a lighting and appliance branch-circuit panelboard equipped entirely with plug-in circuit breakers, fed from a single main breaker. Per NEC 408.36, what is the maximum number of overcurrent protective devices (poles/circuits), not counting the main, that this type of panelboard is permitted to contain?
- A48
- B30
- C42
- D24
Show answer & explanationAnswer & explanation
Correct answer: C. 42
NEC 408.36 limits a lighting and appliance branch-circuit panelboard to a maximum of 42 overcurrent devices (poles), not including the main. This rule prevents overcrowding of panelboards and ensures proper labeling and access.
Why the other options are wrong
- A. 48 exceeds the code-permitted maximum.
- B. 30 is not the recognized code limit for this panelboard type.
- D. 24 is well under the code maximum, not the code limit.
Panelboard 42-Circuit Limit
A lighting and appliance branch-circuit panelboard may contain a maximum of 42 overcurrent protective devices, not including the main, per NEC 408.36.
- Applies to panelboards where more than 10% of OCPDs are 30A or less with a neutral connection
- Main breaker/lugs are not counted toward the 42-circuit limit
- Rule prevents overloaded, hard-to-label panelboards
Memory trick: 'Forty-two and no more' keeps the panel door closing.