I'm considering an appliance that is 240V 16A 3500 Watt with a NEMA 6-20P plug. Is it possible and safe to create an adapter for this so that it can be plugged into a standard 4-prong 14-30R dryer outlet? The adapter would be a typical 4-prong dryer cord with a NEMA 6-20R receptacle.

Would this be possible? NEMA 14 is hot/hot/neutral/ground. Could this be wired to a 6-20 receptacle that is hot/hot/ground? What is done with the neutral? If possible, would it be unsafe because of the 30A circuit and 20A receptacle (or other reasons)?

EDIT: To add some more info, the appliance is an an Avantco IC3500 induction cooktop. It is ETL listed and the label on the bottom states that it complies with UL Std 197, which I cannot find details on with respect to amperage.

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    amazon.com/L14-30P-6-20R-Power-Cord-Adapter/dp/B004XWAKUQ -- These are available commercially – Chris Cudmore Jul 30 '14 at 15:29
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    @ChrisCudmore How is it safe to plug an adapter rated at 20A into a 30A receptacle if not protected by a 20A CB? – Mazura Jul 30 '14 at 21:17
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    Those adapters are home made and not UL listed. If I had to I could make one of those up in about 10 minutes from stock I have on the truck. – Speedy Petey Jul 30 '14 at 22:52
  • rackmountpdu.com/products/… says UL listed, RoHS certified, CSA approved...what gives? – Mazura Jul 30 '14 at 23:29
  • Unfortunately, the 14-30 outlet is not locking (L14-30). – WA Hunt Jul 31 '14 at 15:34

The answer is it depends on the appliance. As long as the appliance does not expressly forbid using it on a 30A circuit you should be fine. You'll be able to change the plug and put on a 14-30P plug, just ignore the silver terminal (neutral).

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    I would err on the side of the manual expressively permitting 30A service or field modifications to the cord. Just because the manual doesn't say you can't, doesn't mean you should. – Mazura Jul 30 '14 at 22:21
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    Still, be careful about the device failing and drawing too much current, which could cause a fire. – Greg M. Krsak Dec 5 '14 at 21:13
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    If you're using a device that's rated at 20A, on a 30A circuit, and the catches fire between 20A and 30A. Not saying it's likely. – Greg M. Krsak Dec 9 '14 at 15:44
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    My point is how would it catch fire? How is it any different than plugging a 1A radio into a 20A circuit? What if the radio catches fire between 1 and 20 amps? Get my point? – Speedy Petey Dec 9 '14 at 18:03
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    @SpeedyPetey That "1A radio" may only draw 1 ampere, but it's designed to carry the full load of the circuit it's connected to (20 amperes). A device with a NEMA 6-20 plug, is not likely designed to handle 30 amperes. The wiring in the device could theoretically catch fire, before the breaker tripped. – Tester101 Oct 9 '15 at 12:44

You could wire a 20 amp breaker into the adapter. Something along these lines would be perfect. Easy to reset as well.

  • Why is this down voted? Connecting an appliance that is meant to be plugged in to a 15 or 20 Amp circuit in to a 30 Amp circuit can be a hazard, and adding a fuse is the right thing to do. Since this device won't be left unattended, it's probably not worth it, but in general the fuse should be added when doing something like this. – Alex Cannon Mar 31 at 15:10

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