Final answer:
The student's question involves electrical load calculations to determine if the existing service can handle a new air conditioner in a mobile home. The service must be upgraded to accommodate the increased load from the existing 43 amps plus the new 3,000 VA air conditioner, as the total new load exceeds the 80% safety threshold of the current service capacity.
Step-by-step explanation:
Service Calculation for a Mobile Home
The student is asking about the changes in electrical load due to replacing an air conditioner in a mobile home. The existing setup has a 240-volt connected load of 43 amps on both legs, and an air conditioner rated at 1,200 VA at 120 volts. With the replacement of the air conditioner with a 240-volt unit rated at 3,000 VA, it is necessary to ensure that the service can handle the added load safely.
To calculate the new load, we first convert the current air conditioner's capacity to watts using the formula Power (W) = Voltage (V) × Current (A). For the 1,200 VA unit at 120 volts, this is not needed since VA (volt-amps) is essentially equivalent to watts in this context. So, the current load = 1,200 W.
Since the new air conditioner is a 3,000 VA unit at 240 volts, its load is also equivalent to 3,000 W. Now, the total new load will be the sum of the existing load (43 A × 240 V × 2 = 20,640 W) plus the new air conditioner load (3,000 W), which equals 23,640 W or about 23.64 kW.
If we assume that the main breaker is rated for 100 amps at 240 volts, then the total capacity of the service is 100 A × 240 V = 24,000 W or 24 kW. Operating at 80% for continuous loads, which is a standard electrical code requirement, the service can handle 19.2 kW safely. Therefore, with a load of 23.64 kW after replacing the air conditioner, the service must be upgraded to handle the increased load. This is above the 80% safety threshold of the currently assumed 100-amp service.
This scenario exemplifies how households equipped with circuit protection must consider total consumption needs, especially when adding more demanding appliances like air conditioners.