What is the minimum number of 15-amp, 120-volt lighting circuits required for a multifamily dwelling of 12,000 sq. ft.?

To determine the minimum number of 15-amp, 120-volt lighting circuits required for a multifamily dwelling of 12,000 sq. ft., it's essential to consider the applicable electrical code requirements, typically based on the National Electrical Code (NEC).

For lighting load calculations, the NEC provides guidelines that help determine the maximum allowable square footage served by one lighting circuit. Generally, the calculation for lighting loads in various occupancies, such as multifamily dwellings, is based on 3 watts per square foot.

First, calculate the total lighting load for the entire 12,000-square-foot dwelling:

Total lighting load = 12,000 sq. ft. x 3 watts/sq. ft. = 36,000 watts.

Next, convert this load into amperes using the formula:

Amps = Watts / Volts

For a 120-volt circuit:

Amps = 36,000 watts / 120 volts = 300 amps.

Since each 15-amp circuit can safely handle only a portion of this total load before overloading occurs, the number of circuits required can be calculated by dividing the total amperage by the amperage of a single circuit.

Therefore, the minimum number of circuits required