Scored a welder. Is it any good?

[patrick_g]

When in doubt hire an electrician. Pat has said it about as clear as anybody. I've been in electronics/electrical work for most of my life and it never ceases to amaze me when anybody has an electrical discussion. My 2 cents are Power (watts) are capacity generated or used. Volts and amps are the medium used to get the job done. If your welder requires 50amps at 240volts then you will need x-sized wire. Because of duty cycle you "may" get away with something smaller. But like I said you "may"....... To wire your shop best advice and to keep you legal and safe is to have an electrician perform the task. Then all you have to worry about is going from the wall outlet to your welder.

LD1 your on the right tract to understanding but keep in mind that when dealing with electrical circuits there isn't a one rule fits all. DC circuits are done differently than AC circuits. Keep on learning. I've been at it for around 50 years and I still find something new each time I work on something that deals with electricity. Here's a challenge derive an AC circuit to get 3phase power out of a single phase line.

Good luck.

Wolfman, Thanks for the ego boost. There is something that has been sort of hinted at around the edges but not stated plainly and that is the difference between equipment (welder performance) and wire sizing/safety.

This is two separate things. Just because your extension cord doesn't melt that is not proof that your equipment is happy with the voltage supplied under load. Old transformer type welders (non-electronic) may not deliver the indicated amps on the dial or switch if the supplied voltage at the welder, under load, is low due to chintzy wire size/length of run supplying the juice.

Nice to make your acquaintance, sir. I too am ex military (4 years of USAF during the little fracas called Viet Nam) and general class ham, first lisc about 1962-3 as KN5DBP (decibel Pat) It is nice to find another electron chaser with sufficient tenure to know what a Fleming valve is (aka tube for the other guys) I was trained on analog computers (flight sim stuff, Link C-11-C for 8 "interesting" months at Chanute Field.

Pat

 

[Eagle Dude]

I was wondering when someone was going to use the good ole water analogy

Quite simply the flow rate isn't going to be the same. a 1/2" ID garden hose @50psi is going flow a lot less than 1/2" ID Hyd Hose @ 3000psi

For this reason is why I have never liked the water analogy. Everyone compairs amps to flow, but with water, increase the pressure, you increase the flow. with electric, if you increase the volts, the watts go up, ant not the amps WRONG.

You missed it on what was said, Both would give the same Flow rate (current) for the same pressure (Voltage) but one would be able to withstand much more pressure than the other before failure (arcing through insulation).

I have been in the electrical/electronic field for over 40 years, 20 of which teaching at the college level. You have had some excellent explanations and yet you will not accept them. I encounter students like this on occasions. You have found something that works for you and are unwilling to accept the reasonable logic that you are in error and to this point have just been lucky. It appears as if you are either acting as the Devils advocate or you don't have the least bit of technical knowledge on electricity. NEC codes are minimum recommendations and are intended to protect life and property damage. Some people can live on the edge and get away with it forever, here's hoping that you never suffer a loss because of your unwillingness to accept.

 

[LD1]

You missed it on what was said, Both would give the same Flow rate (current) for the same pressure (Voltage) but one would be able to withstand much more pressure than the other before failure (arcing through insulation).

I have been in the electrical/electronic field for over 40 years, 20 of which teaching at the college level. You have had some excellent explanations and yet you will not accept them. I encounter students like this on occasions. You have found something that works for you and are unwilling to accept the reasonable logic that you are in error and to this point have just been lucky. It appears as if you are either acting as the Devils advocate or you don't have the least bit of technical knowledge on electricity. NEC codes are minimum recommendations and are intended to protect life and property damage. Some people can live on the edge and get away with it forever, here's hoping that you never suffer a loss because of your unwillingness to accept.

This is exactally the kind of post that wastes everyones time. If all you want to do is tell me "how unsafe I am and t the code is there for a reason" then you are not helping anyone out, just wasting time.

I have said multiple time that I know what the code is, that I want to understant the correct formulas and math for sizing a wire. Certainly the NEC didn't just say this is the way it will be without crunching some #'s.

And never did I say anything about not accepting the explintions that were given to me. Maybe I asked more questions about them, or came up with new questions, but never did I say anyting like you imply.

From now on, let's just say that I never used my welder wiring as an example, and everyting of mine was up to code, and I was just wondering how to come up with correct wire size, and Not by just looking at the NEC book. Because there have been many helpful posts and I have learned a lot, but there are also the post like these, which just state the "code this" and "you are unsafe that". Please all you tend to do is try to lecture me, then don't post.

 

[aczlan]

This is exactally the kind of post that wastes everyones time. If all you want to do is tell me "how unsafe I am and t the code is there for a reason" then you are not helping anyone out, just wasting time.

I have said multiple time that I know what the code is, that I want to understant the correct formulas and math for sizing a wire. Certainly the NEC didn't just say this is the way it will be without crunching some #'s.

And never did I say anything about not accepting the explintions that were given to me. Maybe I asked more questions about them, or came up with new questions, but never did I say anyting like you imply.

From now on, let's just say that I never used my welder wiring as an example, and everyting of mine was up to code, and I was just wondering how to come up with correct wire size, and Not by just looking at the NEC book. Because there have been many helpful posts and I have learned a lot, but there are also the post like these, which just state the "code this" and "you are unsafe that". Please all you tend to do is try to lecture me, then don't post.

One of the reasons to use the code required wire gauge is so if you have a fire you wont have the firemarshal say that you caused it by having a undersized wire powering something. Because then (given how these things seem to go) your insurance company would deny your claim. It isnt worth it to go under the code required gauge on wires.

We have a coffee maker at the hotel where I work that came with a undersized wire on it, it pulls 13 amps and it has a 16/3 power cord. This week I had to replace the plug because the old one had melted and the tabs had melted into the plug an extra 1/2".

Back to welders, what is the gauge of the wires in the cord coming out of your welder? I would not use a smaller cord than the one that comes on the welder.

Aaron Z

 

[LD1]

One of the reasons to use the code required wire gauge is so if you have a fire you wont have the firemarshal say that you caused it by having a undersized wire powering something. Because then (given how these things seem to go) your insurance company would deny your claim. It isnt worth it to go under the code required gauge on wires.


Back to welders, what is the gauge of the wires in the cord coming out of your welder? I would not use a smaller cord than the one that comes on the welder.

Aaron Z

I am not worried about starting a fire. I don't know if I was clear or not, but the 12ga wire that I am talking about is the powercord for the welder. I used it because it is hat I had avaliable. The guy I purchased the welder from had about a 4ft 10ga SO cord on it. I used it to tie into the breaker with the receptical. The 25-30ft of 12ga SO that I had, I put on the welder itself.

None of this wiring is behind walls. It's just strung across the concrete floor. The only part of the wiring that I can't see is the 6-8" that is behind the breaker box cover. I think my odds are much greater to start a fire with the weld spatter than the 12ga cord lying on a concrete floor.

But like I said, I am not worried at all about myself. My questions are to wiring in general, and how the NEC comes up with it's limitations. What formulas (voltage drop, wattage, etc)

PS back to the welders, I pulled the cover off my welder to see the internal wiring. My 12ga SO cord hooks into the top a box (looks about like a motor starter, without the contacts, maybe fuses???)and then there are two power wires directally below where mine hook in. Interestingly enough, the thwo wires are different. One is a stranded 12ga wire and the other is a 10ga solid.
Not if one has been replaced or what but all the other wires inside are stranded, so I am guessing the solid was replaced. See diagram.
So basically, my power cord is hooking to 12ga wires inside the welder.
Maybe I don't even need a 40a Breaker, it's just what I had, and have always ran welders off of. Maybe I will try a 30A breaker to appease some of the code nuts. (I know it's still wouldn't be to code, but it would be closer)

Again, thanks to all who replied with informative info/links/formulas. I have learned a lot and would like to continue to learn more

 

[sreeb]

There was a lot of discussion on wire size and a lot of it was scary.

The numbers in the tables for wire size and breaker size are based on not overheating the conductors so that the insulation fails or surrounding materials catch fire. That is why the numbers are dependant on the insulation type and installation conditions. Do not exceed this. The table factor in the resistance of the wire with gives the heat generated. The allowable temperature is determined by characteristics of the insulation. The rate at which heat is disapated is determined by the installation conditions (conduit, bundle, cable), number of adjacent conductors, nominal ambient temp, and so on. It is an extremely complex multidisiplinary calculation which is why you can't just find it written down somewhere.

The breakers themselve are designed to protect the smallest wire that is supposed to be attached to them. Their performance is something other than just tripping a .001% over their rated load which also complicates analysis.

For long runs, you may also be concerned about the voltage drop on the wire. This may cause you to use even bigger wire. However, a short run and low voltage drop does not permit you to use smaller wire because even a short run can overheat locally.

For a welders line cord you can get away with smaller if you don't crank it all the way up and run continuously. As a beginner, you probably won't. If you notice it observably hot, get more copper.

In the long run, copper is cheap and fires are expensive. Use lots of it, sleep well, and live long.

 

[MikeD74T]

Wow, what a response. Sounds like a lot of ways that hooking up a welder have been tried. I talked to the electrician and work and here's what I plan. 8 guage wire to the recepticle. This will be dedicated to a 40 amp breaker. That should handle about all this welder can throw out. That leaves taking care of times that I have to work on equipment that I can't move close enough to the welder. If the welder works good then I'll just get extra long leads. I remember seeing a Lincoln 225 with 100 foot leads so I figure that'll work. Now if I can score a plasma cutter!!

maranda, YOUR THREAD"S BEEN HIJACKED!!! I'm not going to enter the debate but suggest that you wire as your electrician recommended and buy an extension cord that allows you to move the welder out to larger work. Even if you go to a #6 wire cord it will be cheaper than getting longer welder leads which BTW is discouraged by welder manufacturers. Going up a wire size on the cord compensates for voltage drop over the extended distance. You'd also have to go up a size on welding leads as well. MikeD74T

 

[kebo]

If a 14ga wire is rated for 15amps at ANY voltage why is it rated for 40amps in a 12V system????

The more I research this the more i think I am starting to understand.


Transit: according to my calculations, 240v system with 12ga wire and 40 amps 30ft length = 4.6 volt drop. Which is only 1.9% and is well under the 3% and 5% standards that I have been reading about, so why would the insurance company have a problem with me being under the 2% that you mention????

Like I said, I don't completely understand it., but I have found two calculators online (just google wire size calculator) and entered 30ft @ 40amps and 220/240v and both have said 12ga minimum.

I know what the code says and I know what the standard is for given amperage. All I am saying is that there has got to be more to it than just amerage.

You guys are telling me that it is unsafe and my insurance company better not find out yet I have found two calculators that says it's fine, I am only at 1.9% voltage drop, and I know from experience that it works and the wire does not get hot. So why does the standard say for 40amp that I need at least 8ga wire. What am I missing? There has got to be more to it.

LD1, you need to take a course in Basic AC/DC Circuit theory!! Power in a DC circuit is always a function of voltage times current. In an AC circuit, power is still equal to voltage times current but the power is varying with the voltage. The voltage is swinging from 0 to 120, 120 back to 0, 0 to 120 (but in the opposite direction) and then back to 0 and then it starts all over (substitute 220V for a 220V circuit). Therefore, the power is usually expressed in terms of AVERAGE POWER (Pa=V*Icos) You might study up on how sinusoidial waveforms behave, and how its parameters are calculated in order to understand more about this subject.

 

[jenkinsph]

SO cord rated at 600v is what I use at home and in my bussiness for everything. I think it is the best cord longest lasting and most flexible in cold weather. That said the guage size is what determines the ampacity and the isulation rating determines the maxmum voltage that can be used.


Steve

 

[RobertBrown]

"You might study up on how sinusoidial waveforms behave, and how its parameters are calculated in order to understand more about this subject".

Thanks, that reminds me, I think I need to brush up on my sinusoidial waveforms to. I'm thinkin I may be a little light in that area.