Welding Cable Ampacity Chart
Find the right welding cable size for your amperage and lead length. A longer, thinner cable carries less current — use this chart to pick a gauge that delivers full power without overheating.
Suggested Welding Cable Size by Amps and Lead Length
Find your welding amperage in the left column, then read across to your total lead length (electrode lead plus work lead, in feet) to find the suggested minimum cable size (AWG or MCM).
| Amps | 50' | 75' | 100' | 125' | 150' | 175' | 200' | 250' | 300' | 350' |
|---|---|---|---|---|---|---|---|---|---|---|
| 100 | #4 | #2 | #2 | #1 | #1 | 1/0 | 2/0 | 3/0 | 3/0 | 4/0 |
| 150 | #2 | #2 | #1 | 1/0 | 2/0 | 3/0 | 3/0 | 4/0 | 250 | 350 |
| 200 | #2 | #1 | 2/0 | 3/0 | 3/0 | 4/0 | 4/0 | 350 | 350 | — |
| 250 | #1 | 1/0 | 3/0 | 4/0 | 4/0 | 250 | 350 | — | — | — |
| 300 | #1 | 2/0 | 3/0 | 4/0 | 250 | 350 | 350 | — | — | — |
| 350 | 1/0 | 3/0 | 4/0 | 250 | 350 | 350 | — | — | — | — |
| 400 | 2/0 | 3/0 | 250 | 350 | 350 | — | — | — | — | — |
| 450 | 2/0 | 4/0 | 250 | 350 | 350 | — | — | — | — | — |
| 500 | 3/0 | 4/0 | 350 | 350 | — | — | — | — | — | — |
| 550 | 4/0 | 250 | 350 | — | — | — | — | — | — | — |
| 600 | 4/0 | 250 | 350 | — | — | — | — | — | — | — |
Suggested in-line ampacity for welding cable based on total lead length (distance from power source, per lead). An em dash (—) means the run is beyond typical single-cable guidance — contact us to discuss paralleled cables or larger sizes. This chart is for reference only; consult a licensed electrical engineer for your specific welding application.
How to Use This Chart
1. Know your amperage. Use the maximum output of your welder, not the typical setting — undersized cable overheats at full output.
2. Measure total lead length. Add the electrode lead and the work (ground) lead. A 25-foot electrode lead with a 25-foot work lead is a 50-foot circuit.
3. Pick the gauge at the intersection. When in doubt, go one size larger — thicker cable runs cooler, drops less voltage, and lasts longer.
Why Cable Size Matters for Welding
Welding cable ampacity (current-carrying capacity) is the maximum current a cable can carry without exceeding its temperature rating. An undersized cable absorbs excessive heat, which can melt insulation, create a fire hazard, damage equipment, and starve your arc of current. Longer runs make this worse: resistance grows with length, so a cable that is fine at 50 feet may be undersized at 150 feet.
Frequently Asked Questions
What size welding cable for a 200 amp welder?
#2 AWG up to 50 feet of total lead, #1 at 75 feet, 2/0 at 100 feet, and 3/0 at 125–150 feet. Step up for longer runs.
Class K vs Class M welding cable — which do I need?
Class K (30 AWG strands) is the industry standard and handles most welding jobs. Class M (34 AWG strands) is more flexible and abrasion-resistant — worth it for robotic welding, tight bends, or daily heavy use. We stock both.
Can I use DLO cable instead of welding cable?
Yes — DLO is tougher and carries UL listings that welding cable lacks, making it code-recognized for fixed installations. See our DLO ampacity chart for ratings.
