Final answer:
3. Use the largest of the two load in you calculations. In meeting NEC requirements for service calculations, the correct approachst is to use the large load, which is typically the load of the heating system over the air conditioning unit. This ensures that circuits are not overloaded and that all electric appliances can be operated safely.
Step-by-step explanation:
When considering the service calculations for a window AC unit in relation to the National Electrical Code (NEC), you will want to follow NEC guidelines to determine the appropriate sizing and capacity of electrical circuits to safely and efficiently power both heating and cooling systems in a home.
Option 3, 'Use the largest of the two loads in your calculations', is typically the correct approach according to NEC requirements. This ensures that the circuit is capable of handling the higher load without the risk of overloading, as heating and cooling devices are not likely to operate simultaneously. So, for a AC that draws 8.5 amps at 240 volts and a heater with 12 kW at 240 volts, it would be necessary to calculate the service requirements using the higher load, which in this case is the heater.
Performing a complete load calculation for a home's electrical needs is crucial for safety and compliance with electrical codes. When doing this, you would consider all significant loads, apply standard calculation methods, and determine the minimum service size for the dwelling.