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Allied Encyclopedia - What Do the Letters on Portable Cord Mean?

Tuesday, February 25, 2020

Everyone uses extension cords, from contractors with power tools on major build sites to families powering their holiday lights. With all these seasonal decorations going up using more and more extension cords, we thought it might be worthwhile to define those pesky letters found on some portable cord packaging and on cable manufacturer websites. The same rules apply to extension cords that apply to any other cable: voltage ratings, temperature ranges, environmental resistances, etc. On the packaging of some portable cords (and on all the portable cords on our website), you'll see a set of letters, up to six long, that connote the set of ratings applicable to the cord.

  • S     =    Service. Severe Service Cord, which means the portable cord has been rated for 600 volts (also 277/480 or 480) and may be utilized in place of SJ or SV in extra-severe service. 

    J      =    Junior. Junior is short for Junior Service, which means the portable cord has been rated to 300 volts (also 120 or 120/208 or 120/240 or 240 or 277, but not 277/480). Examples include SJ, SJO, SJOW, and SJT.

    T      =   Tinsel Cord. Only if it is the first letter of the code for a portable cord. Examples include TTXOW.

    T      =   Thermoplastic (if not the first letter of code). This refers to the material the cord jacket is made out of. Thermoplastic material is light-duty and can be used as a consumer-grade portable cord. Examples include SJT, SPT, and SVT.

    E      =   Elastomer. Short for Thermoplastic Elastomer, a flexible thermoplastic that looks and feels like rubber. This refers to the material the cord jacket is made out of. Thermoplastic elastomer material is medium-duty and performs better in colder temperatures than thermoplastic. (If a portable cord does not have a ‘T’ or an ‘E’, it is made of thermoset material, which makes it heavy-duty.) Examples include SEO/SEOW and SJEOOW.

  • N      =   Nylon. Outer jacket material. 

    O      =   Oil Resistant. Only the outer jacket is oil resistant. Examples include SEO, SO, STO, and SVO.

    OO   =   Oil Resistant. Both the outer jacket and the insulation are oil resistant. Examples include SJOOW and SOOW.

    F      =   Fixture Wire. These cables are rated to 90°C. Examples include H07RN-F.

    P      =   Parallel. This cable is parallel-jacketed (conductors are not twisted around each other). Sometimes called "zip cord." Examples include SPT.

    H      =   Heat Resistant. Referred to as heater cord. This is used in UL cord types such as HSJ, HS, HSO, and HSJO. 

    HH   =   High Heat Resistant.

    V      =   Vacuum cord. "V" is the UL marking in parts like SVT and SVO. This is light-duty portable cord, rated for 300 volts. Typically used with vacuum cleaners and other portable cleaning equipment.

    RD   =   Range or dryer cord. Product examples include SRD, SRDE, and SRDT cord.

    W-A =   Weather Resistant. UL approved for indoor and outdoor use. Examples include SEOO-WA and SJTO-WA.

    W    =   Weather and Water Resistant. Portable cord with a W means it’s approved as weather (sunlight, moisture, etc.) and water-resistant and can be used indoors or outdoors. Examples include SEOW and SJOOW.

For a more visual approach - check out our Power Cord Basics video so the next time you’re in the market for some portable cordage either from a manufacturer/distributor or from your local hardware store, you’ll be armed with the right information to make the correct choice for your needs!

Filed Under: Allied Encyclopedia

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