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Discussion Starter #1
I am exploring options for adding a welder outlet to my garage and would appreciate any advice you might have.


My garage panel has no open breaker slots and is set up with only one 230V/20a circuit that is hardwired to the mini-split AC unit. I was wondering if it is safe/legal to run a line from that breaker to a SPDT (on-off-on) switch that could be used to select between the existing AC circuit OR a new 20a welder outlet, but never both at the same time.

Here is the switch:

https://www.homedepot.com/p/Leviton-30-Amp-Industrial-Grade-Heavy-Duty-Single-Pole-Double-Throw-Center-Off-Maintained-Contact-Toggle-Switch-Brown-1287/301447054

The welder (Lincoln 210MP) shows a draw of 14.7 amps, so a 20a breaker should be OK.

All wiring would be matched 12-2 and the current 20a breaker protection would be maintained.

Thanks!

Mike
 

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It'd probably be easier to put in a small subpanel and replace your existing 20-amp breaker with a 50-amp breaker to feed the subpanel. Then just put 2 20-amp breakers in the subpanel and feed the A/C unit from one and the welder outlet from the other. T

hen you could run both at the same time if you wanted to. You'd never have to mess with any switches or worry about forgetting something.
 

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I like Jim’s idea, but its the most expensive option.

It’s perfectly ok to daisy-chain another outlet on that circuit, but you will run the risk of tripping the breaker if you run both. You could simply add a switch (like a light switch) for the AC to shut it off or just use the remote and turn it off when you want to use the secondary outlet.

I personally wouldn’t get carried away with a two-way selector switch for this. It’s massively overkill. (So secretly I like it. LOL )
 

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I would do what JimR outlined......i would probably just go ahead and do a 100amp (common and cheap) sub panel for possible future ussage since your out of breaker slots......

the switch you linked to is a single pole switch i am not aware of a double pole switch (220v) like you want and you would require 12/3 wire not 12/2 for 220v ....unless i missed something...obviously the sub panel would need the correct wire size feeder

a sub panel would probably cost less than the double pole switch if could even find one something like this with breakers and all https://www.homedepot.com/p/Square-D-Homeline-100-Amp-20-Space-40-Circuit-Indoor-Main-Breaker-Plug-On-Neutral-Load-Center-with-Cover-Value-Pack-HOM2040M100PCVP/204836397
 

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What panel do you have?
In some you can add in some tandem breakers on a few 125v circuits to gain some space for another double breaker.
 

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Discussion Starter #6 (Edited)
^^^^^^

It's a Siemens 1212 with a 40a main. Tandem breakers are a no-go

The buried feed wire from the house appears to be aluminum and the conductors measure approximately .175. Based on that, I'm guessing 6ga which can't really support much more than the 40a main.
 

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Discussion Starter #7
the switch you linked to is a single pole switch i am not aware of a double pole switch (220v) like you want and you would require 12/3 wire not 12/2 for 220v ....unless i missed something...obviously the sub panel would need the correct wire size feeder
I believe a SPDT is the correct switch as this application has only a single "line" and two loads. I am referring to NM 12/2 + ground(3 conductors total). That is what is on the AC circuit now.
 

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I agree with adding a subpanel, but don't skimp with a small (like a 6 breaker) panel, go for something with more spaces. My main panel has been space challenged for many years. As a temporary measure I put a couple of tandems in, though they are not approved for my panel. Then I put in a small 6 space panel for a few shop tools. It was handy, but then when I needed more I ended up replacing the small panel with a full sized 24 space one and fed it with a 100A breaker. No more illegal tandems and plenty of spare spaces for expansion.

Just my 2 cents.
 

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^^^^^^

It's a Siemens 1212 with a 40a main. Tandem breakers are a no-go

The buried feed wire from the house appears to be aluminum and the conductors measure approximately .175. Based on that, I'm guessing 6ga which can't really support much more than the 40a main.

you might do more checking ...i dont think they make a Aluminum (direct burried) UF-B wire....so if its aluminum its probably in a conduit and thus is replaceable should you wish to upsize it...

FWIW..........175 is probably 6ga (.168) ......6ga aluminum's ampicity is 50amp ....it may be oversized for the 40amps for voltage drop due to length of the feeder...........6ga COPPER direct burried UF-B wire's ampicity is 55amps

UF-B is the romex type wire that can be directly buried in the ground without conduit and is typically grey in color
 

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I believe a SPDT is the correct switch as this application has only a single "line" and two loads. I am referring to NM 12/2 + ground(3 conductors total). That is what is on the AC circuit now.
I'm not a code expert, but 220 has 2 hots, if you switch it you should break both hots, otherwise you still have a hot going to the appliance. Though a single pole will technically work, you risk the danger of having a hot into either appliance even though you "switched" it off. And, 12/2 has a black, white and ground, technically white is neutral ... though you could probably tape it a different color (though I don't know if that is acceptable by code.)

More 2 cents.
 

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Discussion Starter #12
^^^^^


Conductors are silver in color. Insulation is black-black-gray. There is a layer of mesh and they a gray outer jacket. I don't have access to where it enters the ground.
 

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Discussion Starter #13

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Small three phase disconnects and switches tend to be a lot cheaper than a two pole. Don’t know why that it is, but I see this very often.

Elevator code requires a lot of disconnects, even on the cab lighting. We are required to break the neutral in the disconnects in case of a mis-wire somewhere. Typically you’ll see a three phase/pole switch instead of a two just because of price.
 

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^^^^^


Conductors are silver in color. Insulation is black-black-gray. There is a layer of mesh and they a gray outer jacket. I don't have access to where it enters the ground.
After re-reading this thread, your garage panel sound like it is already a subpanel off your main service panel. There was some discussion in GTT on how to feed a subpanel, both attached to your house and for outbuildings. My interpretation of subpanels is that you have to supply separate neutral and ground in addition to the 2 hots wires (4 wire to subpanel). The ground bonding and separate ground rod is what may be different in the outbuilding panel.

Again, I'm no expert, but you may want to find out if your garage subpanel is fed correctly.

2 cents.
 

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Discussion Starter #16
After re-reading this thread, your garage panel sound like it is already a subpanel off your main service panel. There was some discussion in GTT on how to feed a subpanel, both attached to your house and for outbuildings. My interpretation of subpanels is that you have to supply separate neutral and ground in addition to the 2 hots wires (4 wire to subpanel). The ground bonding and separate ground rod is what may be different in the outbuilding panel.

Again, I'm no expert, but you may want to find out if your garage subpanel is fed correctly.

2 cents.

You are correct. It is a sub.

Upon further inspection, there are 4 conductors total black-black-gray-unisulated
 

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I believe a SPDT is the correct switch as this application has only a single "line" and two loads. I am referring to NM 12/2 + ground(3 conductors total). That is what is on the AC circuit now.

you might do some more checking ....220v requires 3 conductors and a ground ...110v on 2 legs....1 neutral....and 1 ground ....not sure how a SP switch would ever work but i have been wrong before
 

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I believe a SPDT is the correct switch as this application has only a single "line" and two loads. I am referring to NM 12/2 + ground(3 conductors total). That is what is on the AC circuit now.
NO! DPDT! Both legs of a single phase 240V circuit are hot with respect to ground.

As pointed out by several, don't use a switch at all. Simply wire up the additional outlet and manage the load yourself by turning the A/C off when using the welder outlet.

Al
 

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Got it. Now I see what you are saying. Leviton makes a DPDT with 6 terminals, or this is another option I was looking at:


https://www.homedepot.com/p/GE-30-Amp-240-Volt-Non-Fused-Indoor-General-Duty-Double-Throw-Safety-Switch-TC35321/202978650
That DPDT switch will work, but now it's getting pricey. For about the same price or less, you can either change your garage subpanel or add a second subpanel off the first. If the garage sub is small, it my be easier to just rip it out and put a larger one in. Using the same brand/type, you can reuse the existing breakers.

2 cents.
 

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you might do some more checking ....220v requires 3 conductors and a ground ...110v on 2 legs....1 neutral....and 1 ground ....not sure how a SP switch would ever work but i have been wrong before
Two conductors and a safety ground. An appliance like a stove or dryer that requires both 240v and 120v to operate needs 4 wires - the above plus the neutral to feed the 120v elements.

Al
 
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