Cheap Inverters with Undersized Cords (Not extension cords, the Welders Cord)

[JJN]

Received a new 120/220 volt Inverter Welder rated at 29 amps In @ 220 volts. No surprise that the cord attached to the welder is undersized with 14 AWG. The 220v adapter plug is also 14AWG. I read about another cheap Inverter where the attached 6 ft cord was replaced with 10 gauge wiring and the welder was much improved.

I am not saying their is anything wrong with the welder, it has not even been plugged in yet, or that the cord gauge needs to be increased. I do know that with the 14awg cord, output with 240 volts is 140+ amps. Just curious if others have increased the cord gauge and if it made a noticeable improvement. The 14awg is clearly under rated. However, if the circuit board or internal wiring is also under sized its hard to know what, if any, improvement would be made.

[FlyFishn]

I say try it and see what it does first.

For a short cord the draw through there won't matter as much as if you were running 50-100ft of it. You will, however, heat up the wiring. That gets in to the duty cycle of the welder a bit, though.

Wiring is rated based on amperage vs temperature. The more amps you push through a given wire gauge/material (cu/al are different - usually go 1 gauge bigger on al) the higher the temperature. What you don't want to do is heat up the wire so much that the insulation melts which could short out the conductors.

So with the duty cycle of the welder - if it is a light duty machine then you can stand to draw higher current through the wires as your duty cycle means that current draw won't be there for long then you'll have a cool-down period. That cycle should prevent the wire from over-heating. That also has an affect on why welder circuits (dedicated welder circuits) can run larger breakers than the gauge wire in the circuit would normally call for - because the load is intermittent.

The bigger issue in the smaller wire might be voltage drop. You'll just have to try it and see.

All of the dual voltage machines of current times run the adapter cords like what you have. Normally they are the other way around - NMEA 6-50 on the welder end and a 6-50 to 5-15 adapter. Yours has the 5-15 on the welder and the 6-50 on the adapter. That way, on 240v the larger connector is there to take the current.

What does surprise me a bit is the "120v plug" they use on equipment like this (welders, air compressors, etc) use a 5-15p. That is 2 vertical blades. They should use 5-20p's if the amperage is going over 15a - that would be 1 vertical and 1 horizontal blade. The convention in 120v circuits (look around your house and office) is 5-15's so I suppose that's why they do that. But numerically it doesn't make sense as the connectors aren't rated for that extra 5a. And technically, unless a circuit was dedicated to a welder, you shouldn't be running a breaker more than 15a on a 5-15 plug - no matter what the cable size is.

[Woznme]

Seems to be the way of cheap stuff. Instead of adding a bit more copper, they double the insulation thickness and call it good.

[albrightree]

That picture gives me a shiver. How much could go wrong in the hands of an unknowing user. I've worked with Safety&Compliance Officers that would cut that Adapter in half(ordinance company making fusees, detonators, and airbags). That adapter allows 240vac 50Amp into a 5-15 Female. I've made some adapters similar to that, but must keep them locked in a cabinet so factory help can't find them. Is that device UL or FM listed ? Just curious.

I'm sure the welder will work fine. What kind did you get ??

[Kelvin]

Seems to be the way of cheap stuff. Instead of adding a bit more copper, they double the insulation thickness and call it good.

Hey, at least it stays cozy warm longer!

[triptester]

If the machine is rated at 29 amps/ 240 volts you get under 15 amps for each leg which only requires 14 gauge wire.

[JJN]

Great information. Two legs, 14awg with 15 amps each leg on 240v works. However, the breakers are 20 amps each leg on 12/2. With the duty cycle Flyfishn discussed puts it in perspective. However, I would not wire my house with 20 amp breakers servicing 14 awg. The house lighting duty cycle, despite attempts to change it, is more then 20%.

That picture gives me a shiver. How much could go wrong in the hands of an unknowing user. I've worked with Safety&Compliance Officers that would cut that Adapter in half(ordinance company making fusees, detonators, and airbags). That adapter allows 240vac 50Amp into a 5-15 Female. I've made some adapters similar to that, but must keep them locked in a cabinet so factory help can't find them. Is that device UL or FM listed ? Just curious.

I'm sure the welder will work fine. What kind did you get ??

Yeswelder 165A. Their is a video over an hour long of this welder burning 3/32 and 1/8 7018 rods. Max measured output was 140+ using the standard cord and 220 adapter.

No UL marking. It does have a very nice bright yellow label stating "Quality Certificate 1".

[SweetMK]

Wire gauge has a LOT to do with length,, and duration of current flow.

This is probably not the machine that a pipeliner is gonna buy,,
and if the owner of the machine wants to weld 42" pipe,, well that is his choice.

Go look at the connector on the end of a battery cable on a new Honda car,, tiny connector,,
and that connector is probably going to see WAY more amps than this welder,,

But, the Honda has a very low expected cranking duty cycle.

[SweetMK]

On a side note,, if you want to hear your 7 1/4" circular saw run at VERY high speed,,
use that adapter to plug in the circular saw to 240 volts!!

[shovelon]

Plug it in and torture that machine to overload and get it thru the infancy failure. Infancy failure is the ratio of early failure versus late failure. You surely want the machine to fail under warranty, and the seller expects a certain number of early failures. Otherwise the machine would be to expensive to build.

All of my machines are brought to overload or near to it. Surprisingly most quality units are underrated and are hard to overload. The ones that I personally brought to failure had workmanship issues.

[Oscar]

If the machine is rated at 29 amps/ 240 volts you get under 15 amps for each leg which only requires 14 gauge wire.

You can't divide it like that. Whatever amperage the welder does really pull, it will flow through both legs.

Great information. Two legs, 14awg with 15 amps each leg on 240v works. However, the breakers are 20 amps each leg on 12/2. With the duty cycle Flyfishn discussed puts it in perspective. However, I would not wire my house with 20 amp breakers servicing 14 awg. The house lighting duty cycle, despite attempts to change it, is more then 20%.





Yeswelder 165A. Their is a video over an hour long of this welder burning 3/32 and 1/8 7018 rods. Max measured output was 140+ using the standard cord and 220 adapter.

No UL marking. It does have a very nice bright yellow label stating "Quality Certificate 1".

Will you be able to measure the AC amperage of your welder? curious to see what it really pulls at it's maximum output, assuming you can hold the proper tight arc. It will make a BIG difference in the input amperage pulled if you cannot hold the proper arc length, even if the welding current is the same.

[Kelvin]

If the machine is rated at 29 amps/ 240 volts you get under 15 amps for each leg which only requires 14 gauge wire.

I think you're getting mixed up here. If a motor draws 15A at 120V and you rewire it for 240V, yeah, it will only draw 7.5A (on each leg of the 240) but that's because a 240V circuit has two hots and a 120V circuit only has one hot. If a welder (or a motor) draws 29A at 240V, that means it's using 29A on each of the two hot legs.

[M J D]

Actually you are both wrong. The welder will have a different output on 220 vs 110, so the higher output would require more amps, but generally less than double the 110 amps. Wattage would actually be what applies here.

[JJN]

Plug it in and torture that machine to overload and get it thru the infancy failure. Infancy failure is the ratio of early failure versus late failure. You surely want the machine to fail under warranty, and the seller expects a certain number of early failures. Otherwise the machine would be to expensive to build.

All of my machines are brought to overload or near to it. Surprisingly most quality units are underrated and are hard to overload. The ones that I personally brought to failure had workmanship issues.

How is that done? Take a 1/8" rod and bury it into the metal? If its a lame question, I take full responsibility due to my welding ignorance.

You can't divide it like that. Whatever amperage the welder does really pull, it will flow through both legs.


Will you be able to measure the AC amperage of your welder? curious to see what it really pulls at it's maximum output, assuming you can hold the proper tight arc. It will make a BIG difference in the input amperage pulled if you cannot hold the proper arc length, even if the welding current is the same.

Do not own a amp meter, can not measure. This discussion makes me want one though.

[FlyFishn]

Do not own a amp meter, can not measure. This discussion makes me want one though.

I have some meters like these, maybe the same ones. < link (to ebay listing) you can click on. Cheap and work pretty well. I am not 100% sure on the accuracy, but they don't seem to be far off from what I can tell using them - they appear pretty accurate with different loads that correspond to the meter numbers. I use them both on 120 and 240. The 120 I have wired in-line, the 240 (same meter type - reads both voltages) I hard wire in to the tombstone power switch.

[Kelvin]

Actually you are both wrong. The welder will have a different output on 220 vs 110, so the higher output would require more amps, but generally less than double the 110 amps. Wattage would actually be what applies here.

If the welder says it draws 29A @ 240V, I suspect it draws 29A at 240V. If anything, I would expect the mfgr to understate the amp draw, not overstate it.

And if it draws 29A at 240V, then it draws 29A on both hots.

(I have no idea what you're talking about with "double the 110 amps" above. When you increase line voltage and use two hot legs instead of one, you don't need as many amps to get the same power.)

[M J D]

If the welder says it draws 29A @ 240V, I suspect it draws 29A at 240V. If anything, I would expect the mfgr to understate the amp draw, not overstate it.

And if it draws 29A at 240V, then it draws 29A on both hots.

(I have no idea what you're talking about with "double the 110 amps" above. When you increase line voltage and use two hot legs instead of one, you don't need as many amps to get the same power.)

The welders typically put out say 120 amps, give or take max on 110 volt input. The same welder will typically put out 160 or more amps on 220 volt input. If we were talking electric motors at a given load your previous statement would be correct. Another factor is the arc force feature of many inverter welders. At the same given amp output, the welder often provides higher arc voltage when it has more input voltage, which equals a higher wattage. An example, a welder that is rated for say, 100 amp max output on 110 volt input, would probably pull 20 amps, give or take. That same welder output on 220 volt would be say 160 amp give or take, would probably pull 15-18 amps on the 220 volt input, not half of the 110 volt input amps. What you had stated would be correct on something like an electric motor with the same given load.

[Oscar]

motors and different amperage on dual-voltage operation aside, the statement of dividing the current simply does not work, when solely evaluating 1-ph 240V operation. Kelvin and myself are correct with regards to welder 240V operation and input amperage consumption.

[FlyFishn]

All - give me a couple days and I can run some numbers (I can put it in a video format) on the current draw from an inverter machine on both 120 and 240 at the same welding amperage. I should get my inverter today, not sure I'll have time to mess with it much until the weekend, but we'll see. 120v is easy - thats a straight in line meter on a plug/socket, 240 might take some fanigaling as its still wired for the tombstone switch.

The "doubling" or "halving" of the current between 120 and 240v is correct in the sense of wattage - consumed wattage, not wattage going in to the weld. Take an air conditioner for example (120v window or room) or a refrigerator. They are normally rated in watts, not amps. Its fairly simple math - if you have a 1200 watt load on 120v that is 10 amps (yea, there is power factor and a few other fine details but for simplicity's sake - close enough). For the same 1200 watts on 240v it would be 5 amps (not that you normally run a device on dual voltage, although a lot of the inverter welders - maybe most these days - are capable of it).

I would be curious what the same, say, 80 amps output of welding current would be on the input circuit between 120v and 240v. I would imagine they will be fairly close, but my assumption is that the efficiency is lower on 120v therefore the consumed wattage (not amperage) would be higher than it would be on 240v. By lower efficiency I mean it "takes more energy to get the same result". That would mean that the current draw on 120v should be more than double what it is on 240v for equal welding wattage/heat. That is just a hunch... As to measuring welding wattage - I can see if I can find a way to measure it. I do have some 100 amp DC shunts, if I can figure a way to wire them in without cutting up cords I can try it. Amps x Volts = Watts, but the meters I have do the wattage read out also (as well as watt-hrs/kwh).

[Kelvin]

It's pretty simple:
E=IR
VxA=W

If a welder says it draws 29A at 240V, that means that one leg of 120V will draw 29A, and the other leg of 120V -- which will be 180° out of phase from the first leg of 120VAC (thus being 240V with respect to the first leg) -- will also draw 29A. Thus there will be 29A of current traveling through both hot conductors. End of story.

Ignoring losses due to heat and other factors, 29A at 240V will supply (29x240)W = 6960 Watts of power
To get the same amount of power (Watts) out of a 120V circuit, again ignoring losses due to wire heating and other factors, would require 58 Amps.

[M J D]

It's pretty simple:
E=IR
VxA=W

If a welder says it draws 29A at 240V, that means that one leg of 120V will draw 29A, and the other leg of 120V -- which will be 180° out of phase from the first leg of 120VAC (thus being 240V with respect to the first leg) -- will also draw 29A. Thus there will be 29A of current traveling through both hot conductors. End of story.

Ignoring losses due to heat and other factors, 29A at 240V will supply (29x240)W = 6960 Watts of power
To get the same amount of power (Watts) out of a 120V circuit, again ignoring losses due to wire heating and other factors, would require 58 Amps.

True but that doesn't cover maximum output. I have yet to find a dual voltage input machine that has the same maximum output on 110 volt input as it has on 220 volt input. So not so much the end of story. Point being , what may seem to be an undersized cord, really isn't when you factor in higher voltage input. One would have to believe that any 110 volt input specifications on these machines is entirely unrealistic if not outright false. The dead giveaway is the 15 amp adapter cord provided with the machine.

[Kelvin]

[JJN]

+1

Maybe I should have asked the question on an electricians forum

I need coffeeeee....

[Josey]

It wasn't that long ago Dual voltage was a novelty. But now almost every machine has it. I have no concern and feel
safe when the machine comes wired for 240v with a 240 plug to the welder. and a 120v adapter to reduce it to 120
But some machines come with the 120 plug attached to the welder. and an adapter to feed 240 there doesn't seem
to be any transformer or reducer used. I know what used to happen if you accidently fed 240 into a 120 machine
you fried it ! So what is the reason for doing it backwards like that.

[Broccoli1]

+1

Maybe I should have asked the question on an electricians forum

I need coffeeeee....

FlyFishin mentioned the reason for the smaller gauge wired used and allowed. Duty Cycle.

It is common on welding machines.

Old buzzboxes use 12g

My MM252 uses 8g