Select the best answer for the question.
18. How is the minimum circuit ampacity for an air-conditioning condensing unit calculated?
A. Compressor amps [tex]\times[/tex] fan amps
B. ([tex]Compressor amps + fan amps) \times 1.25[/tex]
C. Compressor amps + fan amps
D. ([tex]Compressor amps \times 1.25[/tex])+ fan amps
Answer (2)
Analyze the options and determine which formula aligns with standard electrical codes.
Option A is incorrect because it multiplies the amps.
Option B is incorrect because it applies the 1.25 multiplier to the sum of compressor and fan amps.
Option C is incorrect because it simply adds the amps without accounting for the continuous load.
Option D is correct because it multiplies the compressor amps by 1.25 and adds the fan amps. The final answer is D .
Explanation
Understanding the Problem The question asks for the correct formula to calculate the minimum circuit ampacity for an air-conditioning condensing unit. We need to consider which formula properly accounts for the continuous operation of the compressor and the intermittent operation of the fan, according to standard electrical codes.
Analyzing the Options Let's analyze the given options:
Option A: Compressor amps × fan amps - This option is incorrect because multiplying the amperage values does not align with standard electrical practices for calculating circuit ampacity.
Option B: ( Compressor am p s + f anam p s ) × 1.25 - This option suggests adding the compressor and fan amps and then multiplying the result by 1.25. This approach might seem reasonable as it includes a 1.25 multiplier, which is often used for continuous loads. However, it treats both the compressor and fan equally, which is not entirely accurate since the compressor runs more continuously than the fan.
Option C: Compressor amps + fan amps - This option is incorrect because simply adding the amperage values does not account for the continuous operation of the compressor, which requires an additional safety factor.
Option D: (Compressor amps × 1.25 ) + fan amps - This option multiplies the compressor amps by 1.25 and then adds the fan amps. This is the correct approach because it specifically accounts for the compressor's continuous operation by applying the 1.25 multiplier only to the compressor amps before adding the fan amps.
Determining the Correct Formula Based on the analysis, the correct formula is (Compressor amps × 1.25 ) + fan amps, as it appropriately factors in the continuous load of the compressor.
Final Answer Therefore, the best answer is D .
Examples
Imagine you're setting up the electrical wiring for an air conditioner in your home. To ensure safety and prevent overheating, you need to calculate the minimum circuit ampacity. The compressor, which cools the air, runs almost continuously, while the fan cycles on and off. Using the formula (Compressor amps × 1.25 ) + fan amps, you account for the compressor's constant load and the fan's intermittent operation, ensuring your wiring can handle the load safely. This prevents tripped breakers and potential fire hazards, keeping your home cool and safe.
The correct formula for calculating the minimum circuit ampacity for an air-conditioning condensing unit is ( C o m p ressor amps × 1.25 ) + f an amps . This method accurately accounts for the continuous operation of the compressor and the intermittent operation of the fan. Therefore, the best answer is D .
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