NEC Commercial Electrical Practice Test

Where must branch circuits for lighting and alarms in multifamily dwellings be supplied from?

1. Individual meters

2. A central supply unit

3. Equipment supplying an individual dwelling unit

4. Public power sources

The correct answer is: Equipment supplying an individual dwelling unit

Branch circuits for lighting and alarms in multifamily dwellings must be supplied from equipment that serves an individual dwelling unit. This requirement ensures that each unit maintains its own electrical supply, allowing for greater safety, control, and reliability within each living space. Individual circuits facilitate the management of power distribution and electrical loads specific to each dwelling, which is especially important for emergency alarms and lighting systems that must remain operational regardless of issues that may arise in other units or in common areas. Using equipment that supplies an individual dwelling unit adheres to safety codes and standards set forth by the National Electrical Code (NEC), which aim to prevent electrical hazards and ensure proper functioning of critical systems like alarms and emergency lighting. In the case of emergency situations, having separate circuits increases the likelihood that essential systems will continue to operate independently of the electrical condition of other units. This approach also simplifies troubleshooting and repairs, as issues can be addressed within one unit without affecting others.