Portable Cord Guide

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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

Category Letter Code Definition
Service S Severe Service (600V)
SJ Junior Service (300V)
Jacket E Elastomer
T Thermoplastic (Unless first letter of code - then it designates tinsel cord)
O Oil resistant jacket
OO Oil resistant jacket and insulation
Weather Resistance W Weather resistant
Application V Vacuum 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* Description AWG Size Range Number of Conductors Conductor Insulation Jacket** Temperature Rating*** Voltage Rating
Std. Other
TPT Tinsel Parallel Thermoplastic 27 (Tinsel) 2 0.030 Plastic - 60 - 250
SP-1 - 18 2 or 31 0.030 Rubber - 60 - 300
SPT-1 Service Parallel Thermoplastic - 1/64” Insulation 18 2 or 31 0.045 Rubber

-

 60 75, 90, 105 300
SP-2 - 18-16 2 or 31 0.045 Rubber - 60 - 300
SPT-2 Service Parallel Thermoplastic - 2/64” Insulation 18-16 2 or 31 0.045 Plastic - 60 75, 90, 105 300
SP-3 - 18-12 2 or 31 0.060 Rubber2 - 60 - 300
SPT-3 Service Parallel Thermoplastic - 3/64” Insulation 18-10 2 or 31 0.060 Plastic2 - 60 75, 90, 105 300
TS Tinsel Service 27 (Tinsel) 2 or 31 0.015 Rubber 0.031 Rubber 60 - 125
TST Tinsel Service Thermoplastic 27 (Tinsel) 2 0.015 Plastic 0.031 Plastic 60 - 125
SV Service Vacuum 18 2 or 31 0.015 Rubber 0.030 Rubber 60 75, 90 300
SVE Service Vacuum Elastomer 18 2 or 31 0.015 Elastomer 0.030 Elastomer 105 - 300
SVEO SVE with Oil-Resistant Jacket 18-17 2 or 31 0.015 Elastomer 0.030 Elastomer 105 - 300
SVO Service Vacuum Oil-Resistant Jacket 18 2 or 31 0.015 Rubber 0.030 Neoprene~ 60 75, 90 300
SVT Service Vacuum Thermoplastic 18-17 2 or 31 0.015 Plastic 0.030 Plastic 60 75, 90, 105 300
SVTO SVT with Oil-Resistant Jacket 18-17 2 or 31 0.015 Plastic 0.030 Plastic 60 75, 90, 105 300
SJ Service Junior 18-10 2, 3, 4 0.030 Rubber3 0.030 Rubber2 60 75, 90 300
SJE Service Junior Elastomer 18-10 2, 3, 4, 5 0.030 Elastomer2 0.030 Elastomer2 105 - 300
SJEO SJE with Oil-Resistant Jacket 18-10 2, 3, 4, 5 0.030 Elastomer2 0.030 Elastomer2 105 - 300
SJO SJ with Oil-Resistant Jacket 18-10 2, 3, 4 0.030 Rubber3 0.030 Neoprene-3 60 75, 90, 105 300
SJOOW SJO with Oil-Resistant Insulation & Jacket,
Indoor/Outdoor use		 18-10 2, 3, 4 0.030 Rubber3 0.030 Neoprene-3 60 75, 90, 105 300
SJT Service Junior Thermoplastic 18-10 2, 3, 4 0.030 Plastic3 0.030 Plastic3 60 75, 90, 105 300
SJTO SJT with Oil-Resistant Jacket 18-10 2, 3, 4 0.030 Plastic3 0.030 Plastic3 60 75, 90, 105 300
S Service 18-2 2 or more 0.030 Rubber2 0.060 Rubber2 60 75, 90 600
SE Service Elastomer 18-2 2 or more 0.030 Elastomer2 0.060 Elastomer2 105 - 600
SEO SE with Oil-Resistant Jacket 18-2 2 or more 0.030 Elastomer2 0.060 Elastomer2 105 - 600
SO Service with Oil-Resistant Jacket 18-2 2 or more 0.030 Rubber2 0.060 Neoprene-2 60 75, 90 600
SOOW SO with Oil-Resistant Insulation & Jacket,
Indoor/Outdoor use		 18-2 2 or more 0.030 Rubber2 0.060 Neoprene-2 60 75, 90 600
ST Service Thermoplastic 18-2 2 or more 0.030 Plastic2 0.060 Plastic2 60 75, 90, 105 600
STO ST with Oil-Resistant Jacket 18-2 2 or more 0.030 Plastic2 0.060 Plastic2 60 75, 90, 105 600
STOOW STO with Oil-Resistant Insulation & Jacket,
Indoor/Outdoor use		 18-2 2 or more 0.030 Plastic2 0.060 Plastic2 60 75, 90, 105 600
HPN Heater Parallel Neoprene 18-2 2 or 31 0.045 Neoprene - 90 105 300
HSJ Heater Service Junior 18-2 2, 3, 4 0.030 Neoprene2 0.030 Rubber2 90 - 300
HSJO HSJ with Oil-Resistant Jacket 18-2 2, 3, 4 0.030 Neoprene2 0.030 Neoprene-2 90 - 300
HS Heater Service 14-12 2, 3, 4 0.045 Neoprene2 0.060 Rubber2 90 - 300
HSO HS with Oil-Resistant Jacket 14-12 2, 3, 4 0.045 Neoprene2 0.060 Neoprene-2 90 - 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.

3 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.