How to Build Your Own Welding Extension Cord 50 Amp 

Awesome! Glad you liked it :)

actually in AC there is no "negative" even at 110V or any voltage "negative" is only on DC.... on AC 110 you have Line, Neutral and Ground... on 220V you have Line-Neutral-Line and ground

@@victormanx Not necessarily and not on this one. This is 3 wire 220. Line, line, and ground. No neutral as the line connections alternate this function at 60 hertz here in the U.S.

@@Neverstopbuilding Comment on a comment from 4 years ago. Better late than never I guess. Welder worked good as you can see from my 2003 Cadillac CTS Quarter Panel Change series. Thanks for the reply bud. Keep up the good work. Best Wishes & Blessings. Keith Noneya

If the ground and Junction Box(JB) beep, that is fine. The plug you bought has an integrated grounding tab to the face plate. Really safer that way with a metal JB.

Solder the knock out tabs.

Wrong answer! If it has knock outs you will be getting an OSHA citation even if they are welded in place. They are designed and meant to be popped out so if your using one of these types of boxes at your place of employment you are getting a citation period. Use non metallic boxes that don't have knock outs and make sure the cord has strain relief to avoid an OSHA citation or better yet spend the money to buy one that is made for this purpose.

@@1SGCurt Correct! I was fortunate to be given hundreds of feet of non-compliant extension cords made with SOOW cable (good) and steel boxes (bad) by an employer who wanted everything cleared out for an inspection. Swapped ends for twist-locks and life is good.

Also depends on the duty cycle / how much the welder will be used continuously. From what I understand there is some derating allowed if the duty cycle will be light. At least that is what I remember when researching this when I made a cable for my everlast welder.

With three wires, the black and white are hot and the green is ground. With four wires, the black and red are hot, the green is ground and the white is neutral. This applies to 240vac circuits. The four wire systems are used for electric ranges, electric dryer and other appliances that may have a need for 120vac for a timer or lights that run on 120vac (for instance). Just ensure that both ends of the wires are connected to the corresponding terminals. You don't want the red wire from the power source to connect to the terminal that is intended for ground (green wire) otherwise, much sparks, heat, smoke and fire will result.

A razor blade lol

A standard utility knife works well, just go slow and be careful not to slice your half. Just gently score around the insulation at the length you need exposed, then slice down from that to the end, and pry the insulation open along the scored spot with long nose pliers. I just stripped about 60 ends that way for wire sizes #3-3/0 on a home project. You can actually strip off insulation in the middle of a wire that way for ground conductors, btw. Note that you don't need to press all that hard, just go slower and make more passes to go deeper as needed.

#8 wire should be good

AWG: In the American Wire Gauge (AWG) system, wire size diameters can be calculated by applying the formula D(AWG)=.005·92((36-AWG)/39) inch. For the 00, 000, 0000 etc. gauges you use -1, -2, -3, which makes more sense mathematically than "double nought." This means that in American wire gage every 6 gauge decrease gives a doubling of the wire diameter, and every 3 gauge decrease doubles the wire cross sectional area. Similar to dB in signal and power levels. An approximate but accurate enough form of this formula contributed by Mario Rodriguez is D = .460 * (57/64)(awg +3) or D = .460 * (0.890625)(awg +3). Metric Wire Gauges (see table below) Metric Gauge: In the Metric Gauge scale, the gauge is 10 times the diameter in millimeters, so a 50 gauge metric wire would be 5 mm in diameter. Note that in AWG the diameter goes up as the gauge goes down, but for metric gauges it is the opposite. Probably because of this confusion, most of the time metric sized wire is specified in millimeters rather than metric gauges. Load Carrying Capacities (see table below) Definition: ampacity is the current carrying capability of a wire. In other words, how many amps can it transmit? The following chart is a guideline of ampacity or copper wire current carrying capacity following the Handbook of Electronic Tables and Formulas for American Wire Gauge. As you might guess, the rated ampacities are just a rule of thumb. In careful engineering the voltage drop, insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account. The Maximum Amps for Power Transmission uses the 700 circular mils per amp rule, which is very very conservative. The Maximum Amps for Chassis Wiring is also a conservative rating, but is meant for wiring in air, and not in a bundle. For short lengths of wire, such as is used in battery packs you should trade off the resistance and load with size, weight, and flexibility. NOTE: For installations that need to conform to the National Electrical Code, you must use their guidelines. Contact your local electrician to find out what is legal! Maximum Frequency for 100% Skin Depth Chart This data is useful for high frequency AC engineering. When high frequency AC is conducted by a wire there is a tendency for the current to flow along the outside of the wire. This increases the effective resistance. The frequency listed in the table shows the frequency at which the calculated skin depth is equal to the radius of the wire, and is an indication that above this frequency you should start considering the skin effect when calculating the wire's resistance. Breaking Force for Copper Wire This estimate is based on nick-free soft annealed Cu wire having a tensile strength of 37000 pounds per square inch. AWG gauge Conductor Diameter Inches Conductor Diameter mm Conductor cross section in mm2 Ohms per 1000 ft. Ohms per km Maximum amps for chassis wiring Maximum amps for power transmission Maximum frequency for 100% skin depth for solid conductor copper Breaking force Soft Annealed Cu 37000 PSI 0000 0.46 11.684 107 0.049 0.16072 380 302 125 Hz 6120 lbs 000 0.4096 10.40384 84.9 0.0618 0.202704 328 239 160 Hz 4860 lbs 00 0.3648 9.26592 67.4 0.0779 0.255512 283 190 200 Hz 3860 lbs 0 0.3249 8.25246 53.5 0.0983 0.322424 245 150 250 Hz 3060 lbs 1 0.2893 7.34822 42.4 0.1239 0.406392 211 119 325 Hz 2430 lbs 2 0.2576 6.54304 33.6 0.1563 0.512664 181 94 410 Hz 1930 lbs 3 0.2294 5.82676 26.7 0.197 0.64616 158 75 500 Hz 1530 lbs 4 0.2043 5.18922 21.1 0.2485 0.81508 135 60 650 Hz 1210 lbs 5 0.1819 4.62026 16.8 0.3133 1.027624 118 47 810 Hz 960 lbs 6 0.162 4.1148 13.3 0.3951 1.295928 101 37 1100 Hz 760 lbs 7 0.1443 3.66522 10.6 0.4982 1.634096 89 30 1300 Hz 605 lbs 8 0.1285 3.2639 8.37 0.6282 2.060496 73 24 1650 Hz 480 lbs 9 0.1144 2.90576 6.63 0.7921 2.598088 64 19 2050 Hz 380 lbs 10 0.1019 2.58826 5.26 0.9989 3.276392 55 15 2600 Hz 314 lbs 11 0.0907 2.30378 4.17 1.26 4.1328 47 12 3200 Hz 249 lbs 12 0.0808 2.05232 3.31 1.588 5.20864 41 9.3 4150 Hz 197 lbs 13 0.072 1.8288 2.63 2.003 6.56984 35 7.4 5300 Hz 150 lbs 14 0.0641 1.62814 2.08 2.525 8.282 32 5.9 6700 Hz 119 lbs 15 0.0571 1.45034 1.65 3.184 10.44352 28 4.7 8250 Hz 94 lbs 16 0.0508 1.29032 1.31 4.016 13.17248 22 3.7 11 k Hz 75 lbs 17 0.0453 1.15062 1.04 5.064 16.60992 19 2.9 13 k Hz 59 lbs 18 0.0403 1.02362 0.823 6.385 20.9428 16 2.3 17 kHz 47 lbs 19 0.0359 0.91186 0.653 8.051 26.40728 14 1.8 21 kHz 37 lbs 20 0.032 0.8128 0.519 10.15 33.292 11 1.5 27 kHz 29 lbs 21 0.0285 0.7239 0.412 12.8 41.984 9 1.2 33 kHz 23 lbs 22 0.0253 0.64516 0.327 16.14 52.9392 7 0.92 42 kHz 18 lbs 23 0.0226 0.57404 0.259 20.36 66.7808 4.7 0.729 53 kHz 14.5 lbs 24 0.0201 0.51054 0.205 25.67 84.1976 3.5 0.577 68 kHz 11.5 lbs 25 0.0179 0.45466 0.162 32.37 106.1736 2.7 0.457 85 kHz 9 lbs 26 0.0159 0.40386 0.128 40.81 133.8568 2.2 0.361 107 kHz 7.2 lbs 27 0.0142 0.36068 0.102 51.47 168.8216 1.7 0.288 130 kHz 5.5 lbs 28 0.0126 0.32004 0.080 64.9 212.872 1.4 0.226 170 kHz 4.5 lbs 29 0.0113 0.28702 0.0647 81.83 268.4024 1.2 0.182 210 kHz 3.6 lbs 30 0.01 0.254 0.0507 103.2 338.496 0.86 0.142 270 kHz 2.75 lbs 31 0.0089 0.22606 0.0401 130.1 426.728 0.7 0.113 340 kHz 2.25 lbs 32 0.008 0.2032 0.0324 164.1 538.248 0.53 0.091 430 kHz 1.8 lbs Metric 2.0 0.00787 0.200 0.0314 169.39 555.61 0.51 0.088 440 kHz 33 0.0071 0.18034 0.0255 206.9 678.632 0.43 0.072 540 kHz 1.3 lbs Metric 1.8 0.00709 0.180 0.0254 207.5 680.55 0.43 0.072 540 kHz 34 0.0063 0.16002 0.0201 260.9 855.752 0.33 0.056 690 kHz 1.1 lbs Metric 1.6 0.0063 0.16002 0.0201 260.9 855.752 0.33 0.056 690 kHz 35 0.0056 0.14224 0.0159 329 1079.12 0.27 0.044 870 kHz 0.92 lbs Metric 1.4 .00551 .140 0.0154 339 1114 0.26 0.043 900 kHz 36 0.005 0.127 0.0127 414.8 1360 0.21 0.035 1100 kHz 0.72 lbs Metric 1.25 .00492 0.125 0.0123 428.2 1404 0.20 0.034 1150 kHz 37 0.0045 0.1143 0.0103 523.1 1715 0.17 0.0289 1350 kHz 0.57 lbs Metric 1.12 .00441 0.112 0.00985 533.8 1750 0.163 0.0277 1400 kHz 38 0.004 0.1016 0.00811 659.6 2163 0.13 0.0228 1750 kHz 0.45 lbs Metric 1 .00394 0.1000 0.00785 670.2 2198 0.126 0.0225 1750 kHz 39 0.0035 0.0889 0.00621 831.8 2728 0.11 0.0175 2250 kHz 0.36 lbs 40 0.0031 0.07874 0.00487 1049 3440 0.09 0.0137 2900 kHz 0.29 lbs YOU ARE ALL WELCOME !1

The plug is NEMA 6-50P and the receptacle is NEMA 6-50R.

It appears that the female socket has a brass colored bar connection from the ground to the metal plate. That would provide grinding to the box. At least my socket had that bar when I built mine.

on SOOW wire, or "cord" you do count the ground as it is also in it own insulation so it is a SOOW #6/3 that has Black, White, Green

Yeah it’s crazy right? Now the same thing on Amazon is nothing

I ran 4 wire to the outlet what do I do with the neutral/white wire

ok I have 10-4 the welder has a 50amp plug but statesvit requires 20amp min I tana 30 amp breaker now I'm going to run a larger extension cord instead of 10 I will run 6or 8 that sound om

good info. now I need t find out how much of voltage drop is okay with my machine.

got 40 amps with 8 3 then wanna plug to that 10 3 5 feet extansion cord u think it will be safe

I ended up getting a 4/4. That way I could up grade my welder a not have to worry about it ever.

The NEC wire Chart says 2 AWG will support 50 amps at 33’, but Aleko sells a welder extension cord for $101 and it’s only 8 AWG and 50’. ETL tested, go figure!

Cheaper to just get your own power pole In your backyard. Lol

It doesn't matter. The metal gang box like shown was not designed or intended that way shown here. This requirement can be found in both the national electric code under Article 314, and OSHA. Probably not a big deal for personal use in a house, but would get you in trouble if used commercially or used by employees. What can happen, and I've personally seen it, is the metal knockout plugs get pushed in or otherwise damaged which can cause a shock hazard. A better box would include a hub.

Never Stop Building unless you have earthed the metal box it will become live if a wire comes loose inside or the box cuts into the cable ...

Good point, thanks for sharing. I like to know the why behind the what (rule or whatever else). Will help to know what to look for inspecting before use.

Good points?, fortunately he put the little plastic protector, hopefully it doesn't fall out. Maybe black or duct tape on the inside to prevent a stray knockout?

Never Stop Building LLC Absolutely not!!! But if you loan it out or put it on a job site, maybe they will. In court you would loose. I do have a safety concern. I did not see you connect ground to the box. You should not use Romex connectors on cords. You even pointed out in the video that they are a problem. You could use cord connectors made for that cord. The cord should also have strain relief at the box. I'm sure that it works wonderfully for you and you probably have not had any issues, but incorrect works great right up to the point it doesn't. Always be safe! The life you save may be your own. Respectfully, Kevin

Kevin Coop Very Good Catch. Thank you also for the respectful explanation.

Oh yeah That’s right No sense being a butthead! I just state facts and let people make up their own minds! Be safe. Kevin

@Kevin Coop Hi man. Would you please list all the appropriate components to build an extension cord for my welder? Its max amperage is 240A and we use 220v. May I be ok with a 6AWG gauge for a 35 feet extension cord? I live in Peru. There's no such thing as inspection for extension cords in jobsites here, so it's legal for me to build one. I ask your help because you seem to know better than I do. Thank you :)

Leonardo Rojas The 240 amps is the amps at some voltage around 12 to 24 volts. There should be a name plate on the machine that will give you amps at 220 or 240 volts. My guess would be around 40 or higher. First get cord cap male and female that match the one that came with welder. (Guessing 50 amp rated) No metal box, just cord caps. Then see if you can get fine stranded hard service cable with #6 fine stranded copper. #6/2 with ground. #6 is rated for 55 amperes. Type could be as (SE,SEW,SEO,SEOW,SEOO,orSEOOW). Which ever you can get. Best Wishes! Kevin