To determine the number of general purpose lighting circuits required for a dwelling that is 2200 square feet according to the National Electrical Code (NEC), follow these steps:
1. Determine the required wattage for lighting:
The NEC requires 3 watts of lighting per square foot for a dwelling. For a dwelling that is 2200 square feet:
[tex]\[
\text{Total required wattage} = 2200 \, \text{sq ft} \times 3 \, \text{watts/sq ft} = 6600 \, \text{watts}
\][/tex]
2. Determine the capacity of one general purpose lighting circuit:
A typical general purpose lighting circuit operates at 120 volts and 15 amps. The capacity in watts of one such circuit can be calculated as follows:
[tex]\[
\text{Circuit capacity} = 120 \, \text{volts} \times 15 \, \text{amps} = 1800 \, \text{watts}
\][/tex]
3. Calculate the number of required circuits:
Divide the total required wattage by the capacity of one circuit to find the number of circuits needed:
[tex]\[
\text{Number of circuits} = \frac{6600 \, \text{watts}}{1800 \, \text{watts/circuit}} = 3.67 \, \text{circuits}
\][/tex]
4. Round up to the nearest whole number:
Since you can't have a fraction of a circuit, you need to round up to the nearest whole number:
[tex]\[
\text{Number of circuits} = 4
\][/tex]
Therefore, 4 general purpose lighting circuits are required for a dwelling that is 2200 square feet according to the NEC.
