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I have a situation where the previous homeowner installed a sauna using the dryer plug. You have to unplug one to plug in the other, a setup that is not only ugly with the sauna plug hanging in the air it also seems unnecessary.

What I want to do is install a 240v 30A rotary switch to service one or the other with one circuit wired to the sauna and the other wired to the dryer plug. I have attached pics of the switch I have in mind - please advise as to whether or not it will work.

Thank you! enter image description hereenter image description here

  • Why are you using something that does not appear to be a UL98 listed double throw switch for this duty? – ThreePhaseEel May 25 at 19:30
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    Nosirree. The labeling says flat-out this is a "CE rated" (which really means China Export) and it is simply not rated to touch mains power in any way. As usual, you see the deception where the seller claims the enclosure is UL listed. Well, what the heck does that buy you??? – Harper - Reinstate Monica May 25 at 20:46
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    Is it the old style of dryer plug with 3 pins? – Harper - Reinstate Monica May 26 at 1:53
  • @Harper-ReinstateMonica ... it buys you a fire.... a big bad fire... maybe some electrocution... – J.Hirsch May 26 at 17:29
  • I did something very similar to share a 240V feed to a dryer and my welder. I USED A DPDT 30 amp switch. Based on Harper's answer, your switch is not UL listed. I just couldn't weld when my mom wanted to do laundry and she always won the battle. Most Sauna's require a GFCI protected outlet so keep that in mind as the dryer doesn't. Does your Sauna have a GFCI plug? – JACK May 26 at 20:42
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You can't use that switch, but you don't need it.

You can't use it because it's not UL listed. The shady supplier admits this rather cleverly, saying the switch is CE (China Export lol), but the enclosure is UL listed. rolls eyes Getting a UL listed BOX doesn't make the switch OK.

But it turns out there's nothing wrong with simply installing two receptacles on a 240V/30A circuit. Well, that was easy!

Just don't run the dryer and sauna at the same time. Done!

Oh wait, two little glitches.

First, the sauna needs GFCI protection. Second, I bet you have the obsolete and dangerous 3-prong dryer connection, and those aren't allowed at all anymore, because they can kill you (whether the sauna or dryer is plugged in - worse for the sauna!)

And I bet you don't want to pull a retrofit ground or a new cable from the panel, or else you wouldn't be here.

Fortunately, we can kill 2 birds with one stone.

There's a rule that says you can install a grounded receptacle, even if it isn't grounded, as long as it's behind a GFCI device of some kind. So that's what we do.

  • We install a 30A, 2-pole GFCI breaker back at the panel. And then,
  • We install TWO (count 'em, two) of the modern, new-fangled NEMA 14-30 receptacles.
  • And we label both receptacles "GFCI Protected. No Equipment Ground".
    • Oh yes, and we change the dryer cord to NEMA 14-30, and very important here, follow the procedure to separate ground from neutral at the dryer. Otherwise the dryer can still kill you.
    • And we change the sauna cord to NEMA 14-30. Now if it has a ground wire, we put that on the ground pin of the NEMA 14-30. That's very important too. If you left the ground pin on neutral, the sauna could still kill you (as it can now).

Just like that we're sittin' pretty. Legal as the day is long.

The second socket can be anywhere, but there's no way to get rid of it altogether. As soon as you hardwire the sauna, it becomes a hardwired load that is >50% of total circuit load, and receptacles are not allowed at all, so that knocks the dryer off.

enter image description here

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    @isherwood Set the thermostat to "off" or 0C. – Harper - Reinstate Monica May 26 at 15:48
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    @isherwood first it's my mistake, it's a sauna. But second you don't run those 24x7 unless you're made of money. Much better to heat them up before you plan to use them. – Harper - Reinstate Monica May 26 at 17:21

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