240 Plug Variations Dryer outlet/ MIG welder Question

electronictofu

Hi all,

I am looking at a MIG welder from Harbor Freight, they cut off the demo unit cable, but its 240 for sure, and looks like 3 wire, meaning 3 prong? I have a dryer outlet Id like to use but it's 4 prong (4-wire red,black,white,ground). Can I cut the cord on this welder and wire on the plug that will fit this outlet or is that bad news bears?

Heres the welder:
https://www.harborfreight.com/170-amp-dc-240v-migflux-cored-welder-57865.html

Image of welder cable demo unit cut



And image of my dryer outlet (Id rather buy a 110 Lincoln that wire another outlet right now) but these Harbor Freights are pretty nice for the price!

Thanks in advance pros and DIY'ers.
-Phil

mattmia2

Probably should be protected at 20a instead of 30a but putting a plug on a 240 v appliance to connect it to a 120/240v receptacle isn't a problem, just don't connect the neutral at the plug.

Mad Dog_2

Oh man...We may very well have some electrical experts here, but I'd say you really want a very experienced Licensed Master electrician or Electrical Engineer to give you the Skinny.  I once installed (8)  WM 88 Series oil HW boilers in a Large Housing project. I wire my own boilers, but these were subbed out to an Electrical contractor.  I forget exactly what they did wrong, but something just didn't look Kosher to me.  I think it was wired 220 but only needed 110.  I gently questioned the Electrician who told me to stick to the piping & assembly of the boilers.  Ok......

Time to fire them up...It ran for about 30 seconds until it smoked the motor and transformer.  Cooked!  The same guy wired all of them.   He INSISTED he knew what he was doing.  After the 3rd one smoked,  he admitted defeat..Ha ha 😂 🤣 😆 😄. 

Moral of the story....Wiring is no hobby or DIY project, especially 220....Be careful.  Mad Dog 🐕 

EdTheHeaterMan

It appears that you have an existing outlet for a 240 V 30 Amp appliance

The welder looks like it should be on a 20 amp circuit.

All this means is that you have enough electric to power the welder, and the welder should be protected with a 20 amp circuit protection.

I would remove the outlet and select another outlet with a 20 Amp rating, change the circuit breaker that supplies that outlet from 30 Amp to 20 Amp

Add the matching plug to the welder and you should be good to go.

109A_5

Looks like this receptacle has some issues !!!

Mad Dog_2 said:

He INSISTED he knew what he was doing.

@Mad Dog_2 He did, he just did not know what he 'should' have been doing.

hot_rod

Many of those small homeowners welders can be used with 120 or 240
My 210 EASAB came with a short adapter cord to plug into 120V. But welding is limited to 1/2 amperage

It makes it very portable. The machine will show the circuit requirements on the label

Why the cut cord?

EBEBRATT-Ed

The welder is a 3 wire (2 hot wires and a ground). Your dryer is a 4 wire (2 hot wires , 1 ground wire , and 1 neutral wire.

You could put a 4 wire plug on the welder to match your outlet (just don't connect the neutral)

BUT not code compliant

Do this at your own risk. As others have mentioned your welder looks like it should be protected at 20 amp.

Why not just put in the correct circuit?

WMno57

Circuit breakers in panels are ONLY to protect the wiring in the home/structure. If anything downstream from the outlet needs protection, it is on the appliance manufacturer to provide a fuse in the appliance.

pecmsg

WMno57 said:

Circuit breakers in panels are ONLY to protect the wiring in the home/structure. If anything downstream from the outlet needs protection, it is on the appliance manufacturer to provide a fuse in the appliance.

Not true. 

The manufactures decide what amperage is needed to safely operate the equipment 15, 20, 30, 40. The electrician then runs the appropriate wire size. 

hot_rod

If it is a 200A  machine it may need  a 50A 240V circuit and plug/ receptacle

Here is what a dual voltage setup looks like
I found the 3 prong 50A  receptacle at the depot 

realliveplumber

So if you have an electric drill (remember those) or a fan, or whatever, and it is stamped 2 amps on the unit, you can still plug those into a 15 or 20 amp receptacle.

109A_5

hot_rod said:

Why the cut cord?

Corporate policy ? Maybe the unit was a defective return, and then became a display model. Years ago folks would cut the cord on defective equipment, so the dummies that ignored the defective tag could not get hurt. However it made more work for the repair guy. Safety First.

Security, the thieves may not want to replace the cord.

HomerJSmith

The name plate rating determines the size of the wire powering the appliance. As I recall, vaguely, the current carrying capacity of the wire is rated 25% less than the wire is capable of carrying. The purpose of the breaker is to cut power to the wire in the case of a ground fault condition which could raise the current above what the wire is capable of carrying which would cause the wire to heat up and possibly melt and start a fire. You can always use a larger wire, but never a smaller wire than the rating of the breaker for that reason. The grounding conductor is there to trip the breaker in a ground fault condition in a situation where the metal frame might become energized.

You can never use a 70 amp breaker on a 20 amp wire, because the wire isn't protected. Yes, WMno57, the breaker is there to protect the wire against an over current condition.

HomerJSmith

Even tho the name plate current rating says 20 amps, the manual should tell you the circuit size for that appliance.

jumper

Also make certain that device is for 240; not 215 or something.

hot_rod

Looks like the spec sheet shows 240V 20A power.

So a basic plug like this, plus receptacle.

electronictofu

Dang! This board is on fire, you all rock. Well, the Harbor Freight welder is brand new and only $229, and a used Lincoln which is what Ive owned 3 of at 110v runs a little more pricey. But If I had to ad an outlet and do more mods than just a cable cut I guess Im betting off waiting to find a good MIG that'll fit a standard wall plug. Just hesitant buying used welders and they are pricy for more commonly known brands like Lincoln. I think it's smart to avoid any risks and wait after reading all the comments, although it'd probably be ok, but as said not ideal nor to code.

hot_rod

There are limits in what you can do with a 120v MiG. Welding power and  duty cycle will take a hit, If either are important for the welding you do

I recently bought a spool gun to weld some 1/8 aluminum, it would not weld with the 120V input

Lucky the ESAB Rebel has a switch to allow 240V input by switching to a 240V circuit also. This allows you to weld on the highest settings

120v makes it very portable, with flux core wire you can go anywhere. I took it to a neighbors to weld a broken motorized hospital bed that her husband uses. Welded it right in the bedroom from a standard outlet

The transformers in side of basic MIGs have shrunk and weight is a fraction of the 120 Hobart Handler  I  bought 30 years ago, that recently died


The ESAB Rebel EM 210 can be found online for under a $1000, but much more $$ than the Harbor Freight and other bargain brands