Is a 15 A Circuit Breaker Capable of Handling 10.6 A Maximum Current?

[cseet]

A circuit breaker is rated for a current of 15 A rms at a voltage of 120 V rms. Answer the following questions:
All answers must have three significant digits unless otherwise specified.

1) What is the largest value of I(max) that the breaker can carry? (Unit: A)

answer:

I(max) = 15(rms) / square root of 2
= 10.6A

2) What average power can be supplied by this circuit? (Unit: kW)

P(rms) = I (rms) * V (rms)
= 1.80 kW

pls correct me if I was wrong and pls direct me to the right path...
thanks
cseet

 

[Chen]

Argh, stupid me.

I(max) = 15(rms) / square root of 2 is not correct, it should be:
I(max) = 15(rms) * square root of 2 if I'm not mistaken.

 

[cseet]

Hi chen,

what about the 2nd answer? is it correct?

thanks
cseet

 

[Chen]

Yes, 1.8kW. By the way, you could have noticed that your first answer is wrong because the maximum current cannot be lower than the average current.

 

[cseet]

Thanks Chen... I see that now...
you have a good day
cseet