Is the circuit breaker amperage the rms amperage

  • #1
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Main Question or Discussion Point

The circuit breakers of my house say that they are 15a (the majority of them). The rms voltage is 120v for the outlets, and so the peak voltage is about 170v. I was wondering, if I hypthetically connected the terminals together with a 10 ohm resistor, would the breaker trip? I dont know if the amperage drawn is total amps, or amps at the rms voltage, and so that is what I am asking. I know its not safe to do, and im not going to do it, but I would like to know if it is 15a in general or at the rms, allowing for more amperage at its peak voltages. Thank You.
 

Answers and Replies

  • #2
Grinkle
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  • #3
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http://static.schneider-electric.us/docs/Circuit Protection/Molded Case Circuit Breakers/0100-400 A Frame FA-LA/FA-FC-FH/0600DB0105.pdf

Look at page 2, it has a curve of time at rated current vs trip time. A circuit breaker will take approx 1000 seconds to trip if the current is right at the rated value, according to this graph at least.
Im not exactly sure what it is saying, because no current will be consistantly be drawn out of the outlet, because many times a second, the voltage reaches zero, and thus so is the current.
 
  • #4
jim hardy
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Im not exactly sure what it is saying, because no current will be consistantly be drawn out of the outlet, because many times a second, the voltage reaches zero, and thus so is the current.
I dont know if the amperage drawn is total amps, or amps at the rms voltage, and so that is what I am asking.
The datasheet Grinkle linked describes RMS symetrical current.

Look up "RMS current"
then think about it - fuses amd thermal breakers work by heating an element.
Not surprising they'd be rated in terms of "heating value" of current, would you think ?
 
  • #5
Grinkle
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Thanks, Jim - yes, RMS.
 
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