How do you choose a portable cord, and what do all those letters mean?
If your facility is like most, you work around various chemicals and oils. You use various motors, machines, and tools both indoors and outdoors. When you work outdoors, you experience a fair range of temperature and humidity variations; even on the same day. Suppose you buy a consumer-rated cord to do an industrial job. Is this cord going to save you money? Generally, no.
Practicing the false economics of buying portable cords based on price alone is a common error. However, it is overkill to use only the most expensive cord available. To be cost-effective, you need to use a cord suitable for the application. This is neither as straightforward as many people seem to think nor as complicated as some would have you believe. Understanding portable cords will help you determine which product is best for your application.
Manufacturers make portable cords mostly from three types of compounds: thermoset, thermoplastic elastomer, and thermoplastic.
Thermoset. These cords have heavy-duty-grade or specification-grade rubber jackets. UL designations for these cords are SOOW-A and SJOOW-A. CSA designations for these cords are SOOW and SJOOW.
Thermoplastic elastomer (TPE). These cords have medium-duty-grade thermoplastic elastomer jackets. UL designations for these cords are SEOW-A and SJEOW-A. CSA designations for these cords are STW and SJTW-A.
Thermoplastic. These cords have a light-duty plastic compound jacket. UL designations for these cords are STOW-A and SJTW-A. CSA designations for these cords are STOW and SJTW.
Let's take a closer look at the various types of cords.
Thermoset (rubber) portable cords are extremely flexible and durable. You can use them for indoor or outdoor applications in industrial, commercial, mining, oil and construction environments. They resist cuts, tears, abrasions, and chemicals. Their rubber properties rate from very good to excellent. Rubber is a heavy-duty material for harsh surroundings. The compound also finds use in marine applications, preventing water from wreaking havoc on a cord's integrity. Thermoset portable cords can be water-resistant and, when marked, water submersible.
Thermoset's best features are its temperature and oil-resistant properties. Unlike thermoplastic and TPE, thermoset jackets will not melt when in contact with heated objects or oils: up to 221 DEGRF (105 DEGRC). In temperatures as low as 40 DEGRF below zero, thermoset maintains its flexibility, durability, and resistance to cracking during normal handling. Standard portable cords (SOOW-A) may not perform as expected and may result in downtime or safety hazards. Cords labeled as type SOW-A provide an oil-resistant jacket only; not oil-resistant insulation.
Some manufacturers offer a premium, or specification-grade, portable cord for extremely abusive conditions, such as those found in granite quarries, steel mills, mines, or chemical plants. Here, the cord is under constant abuse and threat of damage.
TPE compounds are lightweight in comparison to the rubber materials you find in thermoset cords. Approved for indoor and outdoor use, TPE is a better choice than plastic materials for some commercial outdoor construction in northern regions. It performs well in cold temperatures (-50 DEGRC / -58 DEGRF). You'll see this type of material in some standard extension cords.
TPE cords resist water, oil, cuts, chemicals, and acid. They also handle exposure to weather, sunlight, and ozone. You can get these in a flame-retardant version. However, the CSA designation for this type of cord (STW) carries no recognition for oil resistance. The agency marks this cable as a "T" type, thermoplastic: a plastic compound.
Although manufactured like a thermoset product and able to perform in temperatures upto 105 DEGRC / 221 DEGF, TPE may not stand up in environments where extreme heat and hot oil are factors. When exposed to such circumstances, the cord may disfigure or melt, making it useless.
Thermoplastic (plastic) jacketed portable cords are the least flexible of the three types, especially in cold temperatures. Weather-resistant, plastic portable cords can perform both indoors and outdoors. These are suitable for light-duty use on construction sites. They're also popular with consumers. The most popular indoor/outdoor extension cords are thermoplastic (SJTW-A). You can use them where you have minimal exposure to chemicals, oil, and deformation (pressure). Using these in harsh industrial applications or in temperatures lower than -20 DEGRC / -4 DEGRF or higher than +60 DEGRC / +140 DEGRF may disfigure or melt your cable.
Before purchasing portable cord, know the application and the environment where you'll use it. The primary factor in choosing a portable cord should not be price; instead, it should be which cord will do the best job. A less expensive, lower grade cord may seem like a better solution in the short run. However, that "cost-saving" cord in the wrong application costs more over the life of the application. The right cord reduces risk, downtime, and replacement costs.
A portable cord is a flexible, moveable cord you can use to power various types of light- and heavy-duty industrial related applications. These may include operating motors in tools and machinery. They also may include temporary installations.
Portable cord usually contains two or more flexible, stranded copper conductors, in gauge sizes from No. 18 AWG through No. 2 AWG. The copper stranding and types of compounds in the insulation and jacket dictate the flexibility and strength of the cord. The jacket and insulation are key to its physical, chemical, and electrical properties. The jacket distinguishes one type of cord from another helping you select the right one.
We use portable cords both indoors and outdoors. We use them in such harsh locales as industrial manufacturing facilities, steel mills, chemical plants, oil rigs, mining and construction sites, and commercial applications. Then we have the gentler environments: amusement parks, sports complexes, theaters, movie and production studios, and marinas.
With all this variety, you can see the importance of differentiating among the types of cords available. You can choose from standard- and specification-grade cords. In many cases, portable cord manufacturers can design and fabricate a customized cord if you have unique application demands.
You have to know the strengths of each type of portable cord and where to use them. Once you do that, then choosing the right cord is simple.
Each letter in a cord designation really does have a meaning. Here's what those meanings are, for the letters associated with portable cable. S: 600V Service cord (first recognized by UL) J: Junior service - 300V Service cord T: Thermoplastic E: Thermoplastic Elastomer O: Oil-resistant outer jacket OO: Oil-resistant outer jacket and Oil-resistant insulation W-A: Approved for indoor and outdoor use (Weather resistant) in USA W: CSA approval for indoor/outdoor use (Weather/Water resistant)