New Test Question on number of 15 noncontinuous circuits

[julian padilla]

The size of a single-family dwelling is 25,117 square feet. The service is 120/240 volts single-phase. Without application of demand factors, what is the minimum number of general use, noncontinuous 120-volt, 15-ampere branch circuits?


1. 45
2. 32
3. 42
4. 14

See steps below:
Step_1: Table 220.12 lists 3VA/sq-ft. Calculate; 25,117 sq-ft x 3 VA/sq-ft = 75,352 VA. (Note: Lighting is considered a continuous load, however, do not apply this demand adjustment as stated for this specific question.)
Step_3: Calculate the power per circuit; P = I x E = 15 amperes x 120 volts = 1,800 VA / circuit.
Step_4: Calculate the number of 15 A circuits; Total Power / Power per Circuit = 75,352 VA / 1,800 VA = 41.86. Therefore, size up to 42 Circuits.

Do y'all agree that 42 circuits is the correct answer to this question?:?

 

[augie47]

without any adjustment factors, yes. Useless # except to show you know how to do math.

 

[Jnorton195]

The size of a single-family dwelling is 25,117 square feet. The service is 120/240 volts single-phase. Without application of demand factors, what is the minimum number of general use, noncontinuous 120-volt, 15-ampere branch circuits?


1. 45
2. 32
3. 42
4. 14

See steps below:
Step_1: Table 220.12 lists 3VA/sq-ft. Calculate; 25,117 sq-ft x 3 VA/sq-ft = 75,352 VA. (Note: Lighting is considered a continuous load, however, do not apply this demand adjustment as stated for this specific question.)
Step_3: Calculate the power per circuit; P = I x E = 15 amperes x 120 volts = 1,800 VA / circuit.
Step_4: Calculate the number of 15 A circuits; Total Power / Power per Circuit = 75,352 VA / 1,800 VA = 41.86. Therefore, size up to 42 Circuits.

Do y'all agree that 42 circuits is the correct answer to this question?:?

I agree that 42 is correct unless you have the total calculated load as stated in 210.11(A). But i think lighting is only considered continuous in commercial or industrial applications. Is this a question that has a different answer listed as the correct answer?

 

[julian padilla]

I agree that 42 is correct unless you have the total calculated load as stated in 210.11(A). But i think lighting is only considered continuous in commercial or industrial applications. Is this a question that has a different answer listed as the correct answer?

I agree with you that lighting should be calculated as continuous, but this course work question (which is not necessarily practical) states NON continuous, that is why I questioned my own calculation, and resultant answer of 42 circuits. So I think I got it correct.
Thanks for your input, I appreciate it.
Julian

 

[charlie b]

You don't need to do any math to demonstrate that the answer is 42. That is, after all, the answer to the ultimate question of life, the universe, and everything! :lol:

 

[JoeStillman]

You don't need to do any math to demonstrate that the answer is 42. That is, after all, the answer to the ultimate question of life, the universe, and everything! :lol:

:happyyes: