Question

Only the shell for an office building is to be built. It is 225 feet long, 90 feet wide, and 10 stories high. Calculate the lighting and receptacle feeder demand in volt-amperes for the building with the number of receptacles unknown.

a) 1,012,500 VA
b) 1,125,000 VA
c) 1,237,500 VA
d) 1,350,000 VA

Answer 1

To calculate the office building's lighting and receptacle feeder demand, we use NEC's standard of 3.5 VA per square foot for lighting and 1 VA per square foot for receptacles, multiplied by the area and the number of floors. The calculated demand is 911,250 VA, which doesn't match the given answer options, indicating a potential error.

Step-by-step explanation:

To calculate the lighting and receptacle feeder demand in volt-amperes (VA) for the office building without a known number of receptacles, we use the National Electrical Code (NEC) standard calculations.

The NEC suggests a basic calculation for commercial buildings that assigns a general lighting load of 3.5 VA per square foot for office buildings. Since we know the office building is 225 feet long and 90 feet wide, we can calculate the building's area:

• 225 feet x 90 feet = 20,250 square feet

Then, we multiply the area by 3.5 VA:

• 20,250 square feet x 3.5 VA/square foot = 70,875 VA

Since this is per floor, and the building has 10 stories, we multiply this value by the number of floors:

• 70,875 VA/floor x 10 floors = 708,750 VA

To account for receptacle loads, we typically add an allowance as per the NEC, which is 1 VA per square foot. Therefore, we again multiply the area of the building by 1 VA:

• 20,250 square feet x 1 VA/square foot = 20,250 VA

Then, multiply this by the number of stories:

• 20,250 VA/floor x 10 floors = 202,500 VA

Finally, we add the lighting and the receptacle loads together to get the total demand:

• 708,750 VA + 202,500 VA = 911,250 VA

However, since none of the provided answer options match this calculated total demand, we should re-examine our calculations and assumptions or check if there was a mistake in the question or answer choices.

Answer 2

The lighting and receptacle feeder demand for a 10-story office building measuring 225 feet by 90 feet is 366,875 volt-amperes using standard NEC calculations and demand factors.

Step-by-step explanation:

To calculate the lighting and receptacle feeder demand in volt-amperes for the office building, the National Electrical Code (NEC) guidelines can be used. We do not have the actual number of receptacles, but we can use standard values given by the NEC. For office buildings, the NEC typically uses 3.5 VA per square foot for general lighting and receptacle loads.

The first step is to calculate the total square footage of the 10-story office building:
225 feet (length) x 90 feet (width) x 10 stories = 202,500 square feet.

Now, multiply the total square footage by the standard VA per square foot:
202,500 sq ft x 3.5 VA/sq ft = 708,750 VA for lighting and receptacles.

However, for the feeder demand, the NEC allows the first 25,000 VA to be calculated at 100%, and the remainder at 50%.
Therefore, (25,000 VA x 100%) + (683,750 VA x 50%) = 25,000 VA + 341,875 VA = 366,875 VA as the demand factor.

Finally, this demand factor is then added to the full non-continuous load plus 125% of the continuous load. Assuming there are no continuous loads (because the number of receptacles is unknown and not specified), this factor alone constitutes the calculated feeder demand:

Therefore, the calculated lighting and receptacle feeder demand for this office building is 366,875 volt-amperes, which is not listed among the options provided in the question (a through d).