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What Size Wire for 50 Amp Welder? – Things to Know

Written by Edwin Jones / Fact checked by Andrew Wright

what size wire for 50 amp welder

When finding out what size wire for 50 amp welder, it’s best to stick to recommendations from building codes. It’s standard practice to use 6-gauge wires on welders with amps between 40 to 50. I use this wire size for a 50 amp welder along with a 50-amp circuit breaker for most tools I wire up.

Want to know why this is the specific 50 amp welder plug wire size requirement? I’ve discussed it in detail below.

Wire Sizes and Amperages are Always Directly Related


Since we’re focusing on these two factors alone (and not others like electrical resistance, distance, and the diameter of a wire), and know that the wire size or gauge is always inversely proportional to any tool’s amperage.

For example, a 15-amp home appliance will only require a 14-gauge wire, while a more heavy-duty 70-amp power tool will need a 4-gauge one. The breaker of 50 amps is fairly high as far as most equipment goes; thus, it falls under larger 6-gauge wiring, which is around 3.6 mm in diameter.

These figures are printed out as building codes or charts that electricians use as a reference when deciding Of course, this only answers the exact question, “What gauge wire for a 50 amp welder?” without taking into consideration other factors.

That said, should you always use a 6-gauge wire when wiring a 50 amp 220v welder? Well, the short answer is no. Try asking 5 different electricians as to what 50 amp circuit wire size to use for this specific answer, and I’m more than willing to bet you’ll get different answers. Read on to know why.

Always Check and Follow the Wiring Instructions of the Welder You’re Using


I can’t emphasize this more, because, ultimately, it’s the manufacturer of the welder that knows it best. I’ve certainly departed from the said rule a number of times and followed the instructions in the manual instead. The welders still worked like a charm.

Below, I’ve compiled certain scenarios that I encountered when wiring a 50 amp welder circuit, which serves to underscore that exceptions have to be made at times.

  • I’ve wired a 5-amp input stick welder using a 50-amp breaker and a 10-gauge wire. I was able to use a smaller sized cable because of duty cycle limitations. Essentially, I attribute this mostly to the fact that welders are not continuously but intermittently used instead. You give them the opportunity to cool off, and every time you do so, the wire does so as well.
  • Some brands, like Hobart, in my case, would even list their recommended wire size as 12-gauge or 14-gauge cable for their tools that go for as high as 130 amps. This is obviously well below the average building codes, but they still work despite the seemingly strange recommendations.

One tip I can give if you’re unsure is to err on the side of larger. Going for a bigger wire size does carry the downside of ending up with thicker, and thus heavier, circuits to deal with. However, you’ll be sure that once you turn on the welder, you won’t get the shorter end of the stick and deal with a fire hazard instead.

There are Almost Always Other Factors You Need to Consider

This question admittedly barely brushes on how most wiring projects for welders go. You can’t ignore other essential factors like the whole distance of wire run and, of course, what circuit breaker to use.

I’d also be surprised if you don’t have to consider voltage drop due to resistance at all. If you do, you may need to decide whether you’ll buy extension cords just to meet the necessary distance.

Also, keep in mind that the longer the cord goes, the more it starts to need a higher-gauge wire. You do this to counteract the possible loss of voltage due to heat and resistance. Remember: once you increase the wire size, you essentially increase its amperage capacity, too.

If you’re still a beginner or need to brush up on the essentials of wire gauges, then I recommend you take the time to watch this video:


For many 50 amp welders, you won’t need to depart too much from what building codes recommend. Always aim to meet them first. Fortunately, this is a specific wire size: 6-gauge. However, this is not an absolute rule, and you can always choose a bigger wire to ensure the wire won’t be running in barely proper working condition once you use the welder regularly.

  • If unsure, trust the instructions provided by the welder’s manufacturer.
  • Don’t forget about other fundamentals like distance, possible voltage drop, and what circuit breaker to use.

Hope you like this article on what size wire for 50 amp welder. If you want me to add anything, let me know in the comments below!

Furthermore, visit these guides to choose the best breaker size and wire size for:

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