An SJO cord is a type of heavy duty portable cord. The letter "S" stands for service, "J" for junior and "O" for oil resistant oil jacket.
This cord is considered heavy duty because of the thermoset rubber jacket. The SJO cord can be used for portable tools, portable appliances and similar machinery. The SJO cable is known for being flexible and resistant to abrasions. These cords are also heat resistant but can still be flexible in cold temperatures. This cord is CSA and UL-approved for indoor and outdoor use. It can be used for commercial, industrial and residential uses as well.