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Discussion Starter · #1 ·
I have a 100 amp panel in the garage that has two circuits that are 30 amp for a old welder the previous owner had. There is one 10/3 that runs from the panel to the first outlet. Then a line that runs from the first outlet to the second outlet.

Seems one breaker is using the black wire as hot and the second breaker is using the red wire as hot and I think both are sharing the same neutral.

First question is that ok?

Second, I want to change the plugs to 50 amp plugs and also change the breakers to 50 amp - I read somewhere that as long as I marked the outlets "For Welder Use Only" it was acceptable by code. Is this ok?
 

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This is acceptable provided the breakers are on different phases, you can't share a neutral with two circuits being fed from the same phase. You can change the plugs and the breakers but you will need to to up size the wire to #6 as #10 is only good for 30A
 

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Discussion Starter · #3 ·
This is acceptable provided the breakers are on different phases, you can't share a neutral with two circuits being fed from the same phase. You can change the plugs and the breakers but you will need to to up size the wire to #6 as #10 is only good for 30A
OK so maybe I should go back to square one. This is what the manual for the welder says:

3.04 Electrical Input Requirements
Plug the input cord into a properly grounded and protected
(fuse or circuit breaker) mains receptacle capable of
handling a minimum of 20 Amperes. The Fabricator 131
requires a 115VAC supply Voltage, the Fabricator 181
requires a 230VAC supply Voltage.
The Fabricator 131’s power cord is equipped with a NEMA
5-15P plug and will only connect to a NEMA 5-15P
receptacle.
The Fabricator 181’s power cord is equipped with a NEMA
6-50P plug and will only connect to a NEMA 6-50P
receptacle.
I have the Fabricator 181 - do I just need to change out the outlet to a 6-50P?
 

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Second, I want to change the plugs to 50 amp plugs and also change the breakers to 50 amp - I read somewhere that as long as I marked the outlets "For Welder Use Only" it was acceptable by code. Is this ok?
This is more than likely legal, but I DO NOT like to do this in a residential setting.

Most home based welders (people, not machines) do not care about duty cycle, and the next owner of the house is not going to care if it says "welder use only". They will plug in their kiln either way.
 

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Discussion Starter · #5 ·
This is more than likely legal, but I DO NOT like to do this in a residential setting.

Most home based welders (people, not machines) do not care about duty cycle, and the next owner of the house is not going to care if it says "welder use only". They will plug in their kiln either way.
So, I should do the breakers and the plugs? Or just the plug based on the information from the manual?
 

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the receptical you need is a NEMA 6-50R. which is a 50A 250V 3 wire. I still don't think that is legal, but maybe it is. IMO in this case the wire should be sized to match the size of the breaker your feeding the equipment with, the breaker is to protect the wire, not the equipment. being a resi situation like pete said, this is the best way to go. commercial and industrial applications are a little diff.
 

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just the plug, you can feed #10's with a 30amp 2pole breaker, leave the breaker alone unless it trips out, then change the wire and the breaker
 

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Discussion Starter · #8 ·
just the plug, you can feed #10's with a 30amp 2pole breaker, leave the breaker alone unless it trips out, then change the wire and the breaker
On a earlier point. To use two welders at the same time do the breakers need to be on different phases?

Right now they are both on the same side.
 

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Just to be sure it's clear, changing the plug should be okay. Changing the breaker should only be done if you change the wire.
 

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On a earlier point. To use two welders at the same time do the breakers need to be on different phases?

Right now they are both on the same side.
most panels the phases are located on every other row. 1st row A phase 2nd row B phase, etc.
 

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So on that question I'm a little confused about what you're saying. You're using a 230V welder or welders. These are going to use 2 hot wires and 1 neutral, so you're running off a 30A double pole breaker and as such you're using both phases of the electric service for each welder.
 

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Discussion Starter · #13 ·
So on that question I'm a little confused about what you're saying. You're using a 230V welder or welders. These are going to use 2 hot wires and 1 neutral, so you're running off a 30A double pole breaker and as such you're using both phases of the electric service for each welder.
Nope, both welders are single phase. The breakers look to be standard 30A breakers. Is that not going to work?
 

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The 30a breaker and #10 wire will most likely be fine for that welder. I have a Miller 180 MIG welder on similar circuit. Rather than install a welder recep I installed the more common recep so I can readily plug in other equipment. Then I made an longer extension cable for the welder with conversion plug and recep. Works great.
 

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Discussion Starter · #15 ·
The 30a breaker and #10 wire will most likely be fine for that welder. I have a Miller 180 MIG welder on similar circuit. Rather than install a welder recep I installed the more common recep so I can readily plug in other equipment. Then I made an longer extension cable for the welder with conversion plug and recep. Works great.
Good idea as I was going to make up an extension cord anyway.

We are also going to run a Thermal Arc ArcMaster 185 at the same time (a friend is coming to do some welding training).
 

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Nope, both welders are single phase. The breakers look to be standard 30A breakers. Is that not going to work?
Wait a second. Do you have a 30A 2-pole breaker (takes up two spaces and has the handles tied together), or do you have two separate 30A single pole breakers? If the former, then you're fine. If the latter, then you need to change it to a double pole breaker.
 

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Discussion Starter · #17 ·
Wait a second. Do you have a 30A 2-pole breaker (takes up two spaces and has the handles tied together), or do you have two separate 30A single pole breakers? If the former, then you're fine. If the latter, then you need to change it to a double pole breaker.
Hmmm...I assumes they were two seperate circuits but I wonder if both breakers are used and the same outlet. I will pull the outlets today and clear this whole mess up!
 

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I think the OP is a little confused about 240 volt circuits.
A 240 volt circuit requires a connection to each leg , don't use the term phase when describing the connects, and hence, the current circuit is a 240 volt circuit. Residential wiring is either single phase 240 or single phase 120.
The welder that this circuit will support requires 240 volts and a 6-50 connection. There is no neutral (white wire) required.
To wire this circuit will require a two pole breaker with a red and black wire connected to the breaker and a ground connected to the ground bus.
The first posting says the current circuit is wired with 10-3 so I'm assuming there is a neutral to the current plug. His new welder doesn't require a neutral so if he tries to use the current wiring, he will have to cap the neutral in the first box.
 

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Discussion Starter · #19 ·
I think the OP is a little confused about 240 volt circuits.
A 240 volt circuit requires a connection to each leg , don't use the term phase when describing the connects, and hence, the current circuit is a 240 volt circuit. Residential wiring is either single phase 240 or single phase 120.
The welder that this circuit will support requires 240 volts and a 6-50 connection. There is no neutral (white wire) required.
To wire this circuit will require a two pole breaker with a red and black wire connected to the breaker and a ground connected to the ground bus.
The first posting says the current circuit is wired with 10-3 so I'm assuming there is a neutral to the current plug. His new welder doesn't require a neutral so if he tries to use the current wiring, he will have to cap the neutral in the first box.
Yes I was confused - thanks for clearing it up!
 

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I think the OP is a little confused about 240 volt circuits.
A 240 volt circuit requires a connection to each leg , don't use the term phase when describing the connects, and hence, the current circuit is a 240 volt circuit. Residential wiring is either single phase 240 or single phase 120.
The welder that this circuit will support requires 240 volts and a 6-50 connection. There is no neutral (white wire) required.
To wire this circuit will require a two pole breaker with a red and black wire connected to the breaker and a ground connected to the ground bus.
The first posting says the current circuit is wired with 10-3 so I'm assuming there is a neutral to the current plug. His new welder doesn't require a neutral so if he tries to use the current wiring, he will have to cap the neutral in the first box.

Maybe my fault on phase, I think of them as phases but I'm inclined to think that it would be better for me to not explain myself and just go with the terminology

Alright I can't entirely help myself as an engineer, I swear if I stopped there I'd have trouble focussing the rest of the day. Apologies in advance.

Correct me if I'm wrong, but AC electricity is a sine wave that goes positive then to zero then to negative then back to zero and repeats, each cycle from zero-positive-zero-negative-zero is a cycle and in the US the frequency of these cycles is 60 Hertz meaning 60 cycles per second. So what is happennng is that the POCO pushes 120 volts on one hot leg, the neutral is a return path that is otherwise a constant zero, so the potential is the difference between the 2 wires and thus 120 volts.

Two hot conductors go to a typical residential service, these each are at 120 volts, but they are 180 degrees out of phase so that when one hot is at it's peak positive the other is at its peak negative. So for 240 appliances they use both hots and the potential difference between the two is 120 + 120, so it's equivalent to single phase 240 volts.

In industrial applications something different is done where the term phase is more correctly used because motors with multiple phases are using the different phases so different segments of the windings are charged differently at any given instant... 3 phase would have 3 hot wires each out of phase by 120 degrees.

For real fun, anyone else ever wire a Lionel train layout with multiple transformers and different power blocks on the tracks? Lionel trains use an 0-20 volt AC supply to the track which is different than many other gage model trains that usually use DC power. It's interesting because the trains generally don't care about polarity, but the plugs for the transformers don't have a larger prong for the hot than the neutral. What this means is that if you have 2 transformers on isolated adjacent track sections, when your train crosses the insulator it's shorting across your house wiring's neutral to hot if both transformers have opposite polarity. One of the transformer's plugs needs to be turned around.

Sorry for the sidetracking, and thanks for bearing with me so I can have a clear head! :)
 
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