In my garage I have an electrical 3-phase dryer. I want to add a new 3-phase air-conditioner. I want to be able to switch between the two of them, by using a 3-phase switch. This way, only one of these two appliances, can work at any given time. In the market, such switches, for residential use are already available for purchase.

I was told by two electricians that I am not allowed to install the switch, because such installation is a violation of the building code. My questions are:

  1. Is my proposed installation of a 3-phase switch a violation of the building code?
  2. If the answer is a 'YES', then why is it so?
  3. If I cannot use this switch, what are my legitimate options to make the dryer and the air conditioner able to only work one at a time?
  • Could you provide a link to the switch you want to use, or at least the make and model number?
    – Tester101
    May 18, 2015 at 10:14
  • Where in the world are you that your dryer and A/C are both three phase appliances? May 18, 2015 at 22:39
  • Also, seems like an XY problem. Why do you need to have them not operate simultaneously? May 16, 2016 at 20:30

1 Answer 1


I really don't know why you couldn't. If the switch is made for residential use for that purpose I don't see why not. They said it was against the building code? Not the electrical code? I could not see why the carpenters would care what the electricians did (building code versus electrical code).

  • If you are going to vote my answer down, do you care to share any thought you passer by'ers? I am trying to get the conversation going. Please share your thoughts also. May 18, 2015 at 6:16
  • We can't really answer the question until we know WTF sort of building code the OP labors under. May 18, 2015 at 23:12
  • I voted down what seemed to be a spurious guess, rather than facts from the NEC or IRC code books. The fact that a licensed electrician said it WASN'T permitted means you should cite a reference that ALLOWS it.
    – HerrBag
    May 22, 2015 at 3:39

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