If I change a 15amp circuit breaker to a 30 amp circuit breaker, do I also have

1. 73

   michiganman567posted 11 years ago

   If I change a 15amp circuit breaker to a 30 amp circuit breaker, do I also have to change the wire?
   
   I got a new air compressor, but it trips the circuit, so I have to change my breaker.  I thought that I would also have to change the wire, but someone told me that I can use the 12 gauge wire that is currently in the wall.

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2. 80

   Slarty O'Brianposted 11 years ago

   if your home has updated wiring and you aren't living in a house where the wiring is from the turn of the last century and your compressor runs on 110 to 120 not 220-240 then changing to a twenty amp fuze to solve your issue is ok.
   
   But you might want to figure out what else is on that circuit and why the compressor is blowing the 15 amp fuze. It will likely be rated to run at much lower than that, but for some reason when it starts up there is a spike in the amps it draws, thus blowing the fuze. It's a common issue with electric motors.
   
   If the line you are running it on also has the fridge on it, for instance, the combined amps might be too high when both are starting at the same time or one is running and the other starts.
   
   If nothing else is running on the circuit the motor on the compressor may be bad.
   Put an amp probe on it when it starts up and see what it is trying to pull. If it is really high you may need a new compressor motor.
   
   But most likely it is a matter of too much on one circuit. I recommend looking in to the following: First find out what is on the circuit. Check what amperage the manufacturer recommends you run it on. Call them if need be, Check the amperage it tries to draw on start up. if below 20 amps switch to a twenty amp fuze or breaker. If above I would start worrying about the motor.
   
   But I would not switch to a thirty amp fuze unless that is what the manufacturer recommends, which is doubtful.

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   1. 73

      michiganman567posted 11 years agoin reply to this

      Thank you for the help Slarty.  I don't think that anything else is on that line.  I will have to double check.

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3. 81

   TGoodeposted 11 years ago

   Check your local electrical codes or get a do-it-yourself home wiring book from one of the large home improvement stores. There is a max breaker amperage for a given wire size.  Typically the maximum breaker size for 12 guage wire is 20 amps; for 14 gauge wire is 15 amps, etc.  A 30 amp breaker is too large for 12 gauge wire and would be unsafe. The presence of 12 gauge wire from a 15 amp breaker is puzzling. Try to check the wiring for this circuit at several points to be sure it is 12 gauge throughout, i.e., that someone has not added a 14 gauge run somewhere and reduced the breaker to keep it safe.  It is possible, of course, that the original breaker went bad and someone replaced it with a 15 amp one.  When you are checking for possible other things on this circuit, don't forget to consider overhead lights and outside lights as well as outlets.

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