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help needed wiring

palumbogio

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Joined
Mar 18, 2012
Messages
12
Hi!

I need help how to wire 2 receptacle together both receptacle are used for a machines ( miller 211 mig and a plasma cutter 50d ) that draw 25 amp
My set up is a cart with the plasma and the mig on a double gang receptacle box with one L6-30 and one 6-50r receptacle in attached to 35' extension
one machine at the time will be turn on so the breaker will be able to handle the load
I have attached a picture of the wiring
 

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Tim The Tool Man

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Mar 1, 2012
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Lehigh Valley, PA
The guys with the code books will probably chime in here but I can tell you that I am pretty sure you cannot wire it the way you describe. I sure it would work well for you for many years without issue but you can't guarantee that in the future somebody else won't inadvertently overload the circuit. Be it a friend, child, or future owner of your building.

Then again overloading the circuit would just pop the breaker, so maybe you could do it. Now I am curious as well! My bet is that it is not going to fly with the code book...
 

Chaz

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Missoula, MT
Dont we do this with all 15 amp 110 outlets? There is no guarantee someone wont plug in two 15 amp hair dryers.
 

BFBOB

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Sep 20, 2011
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No problem. As you say, turning on both machines at once will just trip the breaker, not do any damage. Every house has multiple outlets on a 15-amp breaker - though it would be very easy to exceed 15A with everything turned on. If so, it just trips the breaker. That's its job.
The only thing I see different about your setup is two different types of outlet. I doubt very much that's a violation - as long as the breaker is sized not to exceed the capacity of the WIRE, there's no hazard.
 

Milton Shaw

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Feb 11, 2011
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I would suspect that both units could be "powered on" on the circuit without blowing the breaker but if both were used, cutting and welding at the same time, the breaker should trip. I have a welder and plasma hooked up that way and have had them both on without tripping a breaker, but did not try to use both at the same time. The amp draw on both is low until the arc is struck.
 
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wyliesdiesels

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Modesto, CA
Normally, It is against code because u can overload the circuit via the 50a outlet. Just the same reason u cant have a 20a outlet on a 15a circuit. I dont have my code book in front of me so i cant cite the code at the moment. However, there is an exception that allows this to be done with welders and the overrated outlet must marked 'for welder use only'!

Normally, u would use 10/2 or 10/3 wire for a 30a circuit but if u plan on using flexible cord, u need to get 8/3 or 8/4. This is because flexible cords have a lower ampacity rating than their building wire counterparts and the ground conductor is counted in flexible cord! Use 8/3 if your machine only needs 240v and 8/4 if your machine needs a neutral/120v/240v.
 

Grumpy365

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Brazoria County Texas
Normally, It is against code because u can overload the circuit via the 50a outlet. Just the same reason u cant have a 20a outlet on a 15a circuit. I dont have my code book in front of me so i cant cite the code at the moment. However, there is an exception that allows this to be done with welders and the overrated outlet must marked 'for welder use only'!
Usually, you can go bigger, you just can't go smaller.

If I have a 20 amp circuit, with wire and plugs sized for 20 amps, and I swap the breaker to a 15, it is then a 15 amp circuit regardless of the wire size or plugs on the circuit. It is within code and safe.

If you have a 15 amp circuit, with wire and plugs sized for 15 amps and swap out a 20 amp breaker you have a code violation and a fire hazard.


I think you are backwards.

If I am Thinking wrong, please let me know.
 

VHF

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NW Wisconsin
If I have a 20 amp circuit, with wire and plugs sized for 20 amps, and I swap the breaker to a 15, it is then a 15 amp circuit regardless of the wire size or plugs on the circuit. It is within code and safe.
If you have a 20A circuit with #12 wire and standard 15A recepticles, then it is fine to swap to a 15A circuit breaker.

However, if you have a 20A circuit with #12 wire and actual 20A recepticles (with the T-shaped neutral slot), then swapping to a 15A breaker is a no-no because the 20A recepticles allow the user to plug in a 20A load.

Tools and appliances with a 20A plug require a full 20A circuit--otherwise they would have a normal 15A plug!
 

wyliesdiesels

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Modesto, CA
Usually, you can go bigger, you just can't go smaller.

If I have a 20 amp circuit, with wire and plugs sized for 20 amps, and I swap the breaker to a 15, it is then a 15 amp circuit regardless of the wire size or plugs on the circuit. It is within code and safe.

If you have a 15 amp circuit, with wire and plugs sized for 15 amps and swap out a 20 amp breaker you have a code violation and a fire hazard.


I think you are backwards.

If I am Thinking wrong, please let me know.

That would not be to code!

And 15a outlets are allowed to be on a 20a circuit IF there's multiple outlet on that circuit!

Yes, if u swap a 15a breaker to a 20a thats protecting #14 wire, THEN u could have problems!
 

Grumpy365

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Brazoria County Texas
If you have a 20A circuit with #12 wire and standard 15A recepticles, then it is fine to swap to a 15A circuit breaker.

However, if you have a 20A circuit with #12 wire and actual 20A recepticles (with the T-shaped neutral slot), then swapping to a 15A breaker is a no-no because the 20A recepticles allow the user to plug in a 20A load.

Tools and appliances with a 20A plug require a full 20A circuit--otherwise they would have a normal 15A plug!

I guess, BUT the breaker will trip if you install a 20amp load:dunno: that's what breakers are for.

You are probably right, by code, but if so, it's stupid.
 
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