SJO..What? The meanings Behind The Letters on Electrical Cables

Are you in the market for electrical cord sets or products with cords integrated into them? Have you ever noticed the number of acronyms being thrown around in the product descriptions?

SJTW

SEOW.

SJOOW.

Every one of those letters means something and in this post we'll give you a quick primer on the most useful of the acronyms and what they mean. In a previous post we talked about the different cable jacket materials available, so we'll piggy-back off that a bit and show you how you can determine what the jacket material is just by looking at the cable acronym.

The Letters

a(Note: there are more than just these letters, but these are the most prevalent you will come across.)   

• S - Extra Hard Service. Cables that begin with an S are rated for 600V service.
• SJ - Hard Service. Also called a "Junior Jacket," this cable is rated for 300V service.
• E - Thermoplastic Elastomer Jacket. These cables have a jacket made of thermoplastic elastomer (TPE). 
• T - Thermoplastic Jacket. Confusing, I know, but this is different from a TPE jacket. These cables are made with PVC.
• O - Oil Resistant. Just like it sounds, the outer jacket of the cable is oil resistant.
• OO - The addition of the extra "O" means that the outer jacket and the insulation are both oil resistant.  
• W - Weather and Water Resistant. Cabling rated for outdoor use. 
• No T or E - If the cable you are looking at does not have a "T" or an "E" then it is made of rubber.  

Put It All Together

So let's look at the three examples from the beginning of the post and see what they mean.

SJTW - This is a 300V PVC cable that is weather resistant.

SEOW - A 600V TPE cable that is oil and weather resistant.  

SJOOW - A 300V rubber cable with an oil and weather resistant jacket and oil resistant insulation. 

The More You Know

Hopefully you are now armed with valuable information that can help you in your next purchasing decision. Knowing exactly what you are getting is important and empowering for the consumer... and as one of my favorite childhood cartoons used to say "knowing is half the battle."