What’s the difference between SOOW and SJOOW portable cord? What does that extra ‘J’ mean? How do I know which one to use?

Let’s just start with some basics first, like SOOW and SJOOW cable definitions, and then we’ll talk about their similarities and differences.

SOOW and SJOOW cables are both varieties of “service cord.” Service cord is used in all kinds of appliances and motors for industrial and construction equipment. There are many types, and they are named according to their characteristics. Each attribute is designated by a letter.

Here are the most relevant letters for this article’s purposes:

S – Service cord
O – Oil-resistant jacket
OO – Oil-resistant jacket and insulation
W – Weather-resistant
J – Junior service, rated to 300 volts

SOOW and SJOOW Commonalities

SOOW and SJOOW cords are identical in most respects; they are both flexible, stranded multi conductor cables insulated with a synthetic rubber. They have heavy-duty thermo set jackets, which resist water, oils, solvents, sunlight, ozone, weather, and abrasion. Both are rated from -40°C to +90°C.

SOOW and SJOOW Differences

The physical difference between the two cord types is jacket thickness, making the practical difference a matter of voltage. The SOOW cable has a thicker jacket, so it can accommodate up to 600 volts. The thinner SJOOW can only be used in applications up to 300 volts, and that’s why it has the ‘J’ for “junior service” in its name.

SJOOW and SOOW cable both may be used for portable tools and equipment, portable appliances, and small motors. However, SOOW’s greater voltage rating means the cable is functional in a wider range of applications, including construction equipment, cranes, hoists, and other industrial machinery.

Because SOOW cord can be used in a wider variety of applications, it’s usually offered in a greater selection of gauges and conductor counts than you’ll find with SJOOW cord.

Naturally, the larger O.D. and broader versatility of the SOOW cable makes it more costly than SJOOW. If your application does not exceed 300 volts, you can save yourself some money and go with the junior service cord.