by Jason Becker

Cable Size?

Selecting the right size welding cable for a job can be a very daunting task but it doesn’t have to be. I get this question a lot when I cover welding in the field.

I have seen many instances where the incorrect size cable was used and damage to the welding cable has been the result. Many times, the incorrect cable is selected to do the job simply due to the cost per linear foot of the cable. However, cost should not be the driving factor when selecting the right cable for the job.

In order to select the right size cable, we have to ask ourselves 3 very important questions.

  1. How far from the power source will I be welding?

  2. What is my anticipated amperage that I need to do the job correctly?

  3. What is the rated output and duty cycle of my machine?

In order to perform our task safely, we should ensure that the cable we intend to use will support the necessary current required to do the job. Welding cable is made up of fine strands of copper wire, the wire is coated with an insulator and an exterior coating of synthetic or natural rubber. The exterior jacket helps with flexibility, resists abrasions, and keeps the copper inner core from coming in contact with the workers and environment. The insulation of the cable is rated by the ability to with stand heat.

The typical ratings are 167°F (75°C), 194°F (90°C), and 221°F (105°C). The copper strands inside can withstand much higher temperatures but the coating would melt prior to this and could result in a fire. These cables are typically rated for an ambient temperature of 86°F (75°C). Higher temperatures can result in decreased current carrying capacity so a larger diameter may be needed for the job.