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Portable Cord Guide

What is Portable Cord?

Portable cord, also referred to as flexible cord, extension cord or portable cordage, is a multi-conductor cable used for temporary electrical connections. Flexibility is a key feature, as portable cord applications often involve moving equipment like power tools or appliances. Portable cord is used for a variety of applications, from industrial equipment to home extension cords. They also can be made for environmental conditions like water, oil or extreme temperatures. These different applications are noted using a system of letter code designations.


Portable Cord Letter Codes

Portable cord attributes are designated with a system of letter codes that are defined by UL. These codes help understand jacket and insulation, service voltage, duty and heat/oil resistance. These codes can be broken down using the table below.

Portable Cord Letter Code Anatomy

CategoryLetter CodeDefinition
ServiceSSevere Service (600V)
SJJunior Service (300V)
JacketEElastomer
TThermoplastic (Unless first letter of code - then it designates tinsel cord)
OOil resistant jacket
OOOil resistant jacket and insulation
Weather ResistanceWWeather resistant
ApplicationVVacuum cord

UL CORD CONSTRUCTION AND RATINGS

Knowing how to define each letter in a portable cord code is one thing, but it doesn’t necessarily make it easy to find the right cord for your application. Using the table below, we’ve broken down the specifics of most types of UL rated portable cord.

Cord Type*DescriptionAWG Size RangeNumber of ConductorsConductor InsulationJacket**Temperature Rating***Voltage Rating
Std.Other
TPTTinsel Parallel Thermoplastic27 (Tinsel)20.030 Plastic-60-250
SP-1-182 or 310.030 Rubber-60-300
SPT-1Service Parallel Thermoplastic - 1/64” Insulation182 or 310.045 Rubber

-

6075, 90, 105300
SP-2-18-162 or 310.045 Rubber-60-300
SPT-2Service Parallel Thermoplastic - 2/64” Insulation18-162 or 310.045 Plastic-6075, 90, 105300
SP-3-18-122 or 310.060 Rubber2-60-300
SPT-3Service Parallel Thermoplastic - 3/64” Insulation18-102 or 310.060 Plastic2-6075, 90, 105300
TSTinsel Service27 (Tinsel)2 or 310.015 Rubber0.031 Rubber60-125
TSTTinsel Service Thermoplastic27 (Tinsel)20.015 Plastic0.031 Plastic60-125
SVService Vacuum182 or 310.015 Rubber0.030 Rubber6075, 90300
SVEService Vacuum Elastomer182 or 310.015 Elastomer0.030 Elastomer105-300
SVEOSVE with Oil-Resistant Jacket18-172 or 310.015 Elastomer0.030 Elastomer105-300
SVOService Vacuum Oil-Resistant Jacket182 or 310.015 Rubber0.030 Neoprene~6075, 90300
SVTService Vacuum Thermoplastic18-172 or 310.015 Plastic0.030 Plastic6075, 90, 105300
SVTOSVT with Oil-Resistant Jacket18-172 or 310.015 Plastic0.030 Plastic6075, 90, 105300
SJService Junior18-102, 3, 40.030 Rubber30.030 Rubber26075, 90300
SJEService Junior Elastomer18-102, 3, 4, 50.030 Elastomer20.030 Elastomer2105-300
SJEOSJE with Oil-Resistant Jacket18-102, 3, 4, 50.030 Elastomer20.030 Elastomer2105-300
SJOSJ with Oil-Resistant Jacket18-102, 3, 40.030 Rubber30.030 Neoprene-36075, 90, 105300
SJOOWSJO with Oil-Resistant Insulation & Jacket,
Indoor/Outdoor use
18-102, 3, 40.030 Rubber30.030 Neoprene-36075, 90, 105300
SJTService Junior Thermoplastic18-102, 3, 40.030 Plastic30.030 Plastic36075, 90, 105300
SJTOSJT with Oil-Resistant Jacket18-102, 3, 40.030 Plastic30.030 Plastic36075, 90, 105300
SService18-22 or more0.030 Rubber20.060 Rubber26075, 90600
SEService Elastomer18-22 or more0.030 Elastomer20.060 Elastomer2105-600
SEOSE with Oil-Resistant Jacket18-22 or more0.030 Elastomer20.060 Elastomer2105-600
SOService with Oil-Resistant Jacket18-22 or more0.030 Rubber20.060 Neoprene-26075, 90600
SOOWSO with Oil-Resistant Insulation & Jacket,
Indoor/Outdoor use
18-22 or more0.030 Rubber20.060 Neoprene-26075, 90600
STService Thermoplastic18-22 or more0.030 Plastic20.060 Plastic26075, 90, 105600
STOST with Oil-Resistant Jacket18-22 or more0.030 Plastic20.060 Plastic26075, 90, 105600
STOOWSTO with Oil-Resistant Insulation & Jacket,
Indoor/Outdoor use
18-22 or more0.030 Plastic20.060 Plastic26075, 90, 105600
HPNHeater Parallel Neoprene18-22 or 310.045 Neoprene-90105300
HSJHeater Service Junior18-22, 3, 40.030 Neoprene20.030 Rubber290-300
HSJOHSJ with Oil-Resistant Jacket18-22, 3, 40.030 Neoprene20.030 Neoprene-290-300
HSHeater Service14-122, 3, 40.045 Neoprene20.060 Rubber290-300
HSOHS with Oil-Resistant Jacket14-122, 3, 40.045 Neoprene20.060 Neoprene-290-300
NOTE: Service parallel types all thickness for integral construction includes insulation and jacket combined. Elastomer is a thermoplastic material with elastomeric properties similar to rubber.

* Types SVO, SVTO, SJO, SJOOW, SJTO, SO, SOOW, STO HSJO and HSO have jackets which are also recognized for oil resistance at maximum temperature of 60C. Types SJ, SJO, SJT, SJTO, S, SO, ST and STO may also be printed as “OOW” infering an oil resistant insulation and an oil resistant and moisture resistant jacket. Acceptable for indoor/outdoor use. 3-wire SJT may be made in special low-leakage constructions for medical equipment cords.

** Where no jacket is shown, the construction is integral or flat style with insulation also serving as jacket.

* Types SVO, SVTO, SJO, SJOOW, SJTO, SO, SOOW, STO HSJO and HSO have jackets which are also recognized for oil resistance at maximum temperature of 60C. Types SJ, SJO, SJT, SJTO, S, SO, ST and STO may also be printed as “OOW” infering an oil resistant insulation and an oil resistant and moisture resistant jacket. Acceptable for indoor/outdoor use. 3-wire SJT may be made in special low-leakage constructions for medical equipment cords.

** Where no jacket is shown, the construction is integral or flat style with insulation also serving as jacket.

Insulation and jacket thickness depend on cordage size. No. 12 AWG requires .030” conductor insulation thickness and .045” jacket thickness. No. 10 AWG requires .045” conductor insulation thickness and .060” jacket thickness.

Chlorosulfonated polyethylene and other UL Listed materials may be used as jacketing material for such cordage as SVO, SJO, SO and HPN to provide oil resistance and/or colors with excellent stability in all shades.

NOTE Types TPT, SPT-1, SPT-2, SPT-3, HPN (two conductors only) and SVO, SVT, SJO, SJT, SO and ST may be made in retractile form.

The term Elastomer refers to thermoplastic elastomer.

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