Another 220V plug question NEMA 14-30R to 6-20R?

[Dipan Patel]

I have all dryer plug outlets in my shop with 30 amps each. They are four wire 30 amp NEMA 14-30R outlets in a double gang box. My dust collector (Oneida) comes with a NEMA 6-20P plug end and needs a 6-20R receptacle. If I convert the outlet for it to a 6-20R (I am comfortable with this), can I use the other space in the double gang box for a regular 120V outlet? If so, how would I do that? Use ground, neutral, and either one of the hot's?

[Mike Heidrick]

Cut the plug off the Oneida and put on a 14-30 plug. Wire for two hots and a ground. Done.

Yes is the answer to your question on wiring a 120 receptacle from the 4 wires.

[Dipan Patel]

Cut the plug off the Oneida and put on a 14-30 plug. Wire for two hots and a ground. Done.

Yes is the answer to your question on wiring a 120 receptacle from the 4 wires.

Thanks Mike. I already bought the 6-20R receptacle so I will just put a 120v receptacle in the box next to it. Thanks for confirming.

[John Lanciani]

Thanks Mike. I already bought the 6-20R receptacle so I will just put a 120v receptacle in the box next to it. Thanks for confirming.

What size is the breaker? It is not code compliant to use a 6-20R on a 30 amp circuit.

[Dipan Patel]

What size is the breaker? It is not code compliant to use a 6-20R on a 30 amp circuit.

30 amps... What is the rationale? Would it be code compliant to graft a dryer plug on my dust collector instead?

[Jim Seyfried]

30 amps... What is the rationale? Would it be code compliant to graft a dryer plug on my dust collector instead?

I would be more concerned with the 120v part of the circuit, it will be protected with a 30amp 2 pole single throw switch. I wouldn't do it that way and while I don't know for sure, I doubt if it would be to code. And you would have 30amp potential on a 120v plug.

[Jason Beam]

30 amps... What is the rationale? Would it be code compliant to graft a dryer plug on my dust collector instead?

The rationale is the breaker protects your wire and outlets. All of them should match (or worst case, never have a higher breaker than the components). Yes, it's code compliant to plug into an outlet served by a 30a breaker - code doesn't really do much about what you plug into it -- that's up to the device.

If you must use that 20a outlet, i'd change the breaker to 20a as well.

[Dipan Patel]

The rationale is the breaker protects your wire and outlets. All of them should match (or worst case, never have a higher breaker than the components). Yes, it's code compliant to plug into an outlet served by a 30a breaker - code doesn't really do much about what you plug into it -- that's up to the device.

If you must use that 20a outlet, i'd change the breaker to 20a as well.

Thanks. That makes sense. I didn't pause to think that the outlet itself has specific amperage rating and was just thinking of it as different pin configuration/interface. I will use a dryer plug and graft it onto the DC.