4 AWG Welding Cable Class M UL/CSA Orange Cable

• Medium-duty welding applications
• On-site construction welding
• Field repairs
• Mobile welding services

Both are 600V copper welding cables; the difference is stranding. Class M, like this cable, uses fine 34 AWG strands, so it bends, coils, and routes more easily than Class K of the same gauge. That makes it the better pick when leads move constantly, run through tight spaces, or are handled all day. Its CPE jacket is UL/CSA listed and MSHA approved. Class K uses coarser 30 AWG strands and an EPDM jacket and costs less per foot, so it suits more stationary applications without constant movement.

Match the filler wire to your metal thickness and machine. As a rough guide: .023"–.024" for thin sheet and auto body work; .030" for light fabrication up to about 1/4"; .035" for general shop, trailer, and structural work from 1/8" to 1/2"; and .045" or larger for heavy plate on machines above 300A. Use solid wire with shielding gas indoors and flux-cored wire outdoors or on thick, rusty steel. Welding cable is sized separately, by your machine’s maximum amperage and the total length of the electrode and ground leads.

• Size the cable to your welder’s max output and total lead length; undersized leads overheat.
• Turn off the welder before connecting or swapping leads.
• Inspect jackets every shift and replace damaged sections instead of taping them.
• Keep lugs and connectors tight; loose ones overheat.
• Clamp the ground on clean metal close to the weld.
• Fully uncoil leads before welding.
• Keep leads out of water and away from sharp edges, hot slag, and traffic.
• Never wrap leads around your body.

• Use lugs and connectors rated for Class M fine stranding, and crimp with the matching die. Class K tooling can leave fine strands loose and create a hot spot at the terminal.
• Add strain relief at each connection. A cable that bends easily concentrates movement at the lug.
• Don’t treat flexibility as permission to kink. Avoid tight bends and twisting under load.
• Inspect the CPE jacket most often where the cable drags or flexes, and keep it off hot workpieces.

 4 AWG Class M fits battery cables in cramped engine bays and boat hulls, winch leads that flex with the bumper, golf cart and mobility scooter batteries, and inverter wiring in van builds. Check local code before using welding cable for permanent building wiring.