I have existing 220v 30amp circuit not being used. I’m installing 2hp motor on table saw that requires 220v 20amp service. Can I use the 30amp circuit?

  • 1
    Does the existing circuit have a ground wire, or only a neutral? – Harper - Reinstate Monica May 8 '19 at 7:48
  • 1
    Do you have the manual for this saw? If so, what does it say about the breaker requirements, specifically, does it say that the breaker is not to be larger than 20 A? – Jim Stewart May 8 '19 at 10:14
  • Can you post a photo of the receptacle/outlet for the existing circuit? Also, does it run from the main panel, or from a subpanel? – ThreePhaseEel May 8 '19 at 11:35
  • Will it be used again in the foreseeable future? – Harper - Reinstate Monica May 8 '19 at 17:45
  • It depends, but probably not. If the 30 amp circuit is 150% larger than the saw FLA or mfg breaker size you would need to change the breaker down to 20 amp. BUT, there is an exception for motor loads that if the breaker trips on start up you can go to the next size up breaker. However I doubt that you will have tripping problems if the mfg recommends a 20 amp breaker. – Ed Beal May 9 '19 at 0:47

The short answer is yes. The basic parameters are acceptable. However, a load like this is not like plugging in a table lamp. The power supply for this saw must meet a number of safety and professional standards; wire size, breaker size, wire terminations, length of run, among them. And, you can shorten the life of the saw motor if you neglect even one.

| improve this answer | |
  • Probably not as a 20 amp load will be more like 16 amp draw and there is a max of 150% of the rated size - – Ed Beal May 9 '19 at 0:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.