Electrical extension cords aren’t exactly “tools” in the traditional sense, but they are essential on many jobs to power tools and temporary lighting, for bringing power from generators to field offices, and for many other uses.


As essential as they are, many cords are made in China and sold through one or several distributors. Information about the cords can be difficult to obtain.As such, potentially dangerous counterfeit cords are problematic for this market and require diligence to identify.


“More than 1 million counterfeit electrical products, including extension cords and power strips, have been recalled in recent years,” said Brett Brenner, president of the Electrical Safety Foundation International (ESFI), Arlington, Va. (www.esfi.org).


Sources agree that, when selecting extension cords, consider cable ampacity, insulation service rating, cord length, and any restrictions on plugging multiple cords together.


“Electricians should be able to properly select an extension cord and not overload it,” said Bob Wersen, president of Interpower Corp., Oskaloosa, Iowa. “The problem is that extension cords are frequently selected by other trade personnel without regard to safety. The most common mistake all users make in specifying extension cords is to purchase the cheapest cord they can find at a big box store. It may get the first job done, but it will rarely have a very long life. And, when it fails, it can be dangerous.


“The most common mistakes in using extension cords is to select a cord with too low a current rating for the load or to select a cord with inadequately robust insulation for the application.”


Interpower is a supplier of power system components and American-­made cords and cord sets.


Wersen said the most important recent change in extension cords is the availability of high-performance insulation systems that reduce the chance of cutting or abrasion damage.


“Extension cords using high-
performance cables are not generally available, because cheap extension cords from China have driven out most other suppliers who might otherwise offer high-performance extension cords,” he said. “Plugs and connectors have not changed in recent years.”


Wersen said the extension cords that are immediately available typically are chosen, regardless of ampacity and the service rating of the insulation.


“However, inadequate ampacity is a safety hazard when the cord is overloaded for moderate to long periods of time,” he said. “Disregard of the service rating of the insulation usually leads to premature failure of the insulation and is the main cause of short extension-cord life. It can also be very hazardous. Length of an extension cord should be a consideration because the user will want to use the shortest cord that will do the job in order to minimize voltage drops and potential trip hazards.”


General Cable is a manufacturer of copper, aluminum, and fiber cable products based in Highland Heights, Ky. It sells extension cords under the Carol brand.


Carrie Vidal, Carol cord and cordset products manager, said: “Contractors, including electricians, choose an extension cord based on its AWG size, durability, color for easy identification and visibility on a job site; whether it has molded ends so the plug does not pull away from the cord; and lighted ends to see that power is running through the cord. Contractors also tend to prefer rubber cord over plastic due to the flexibility in cold temperatures and resistance to chemicals, sun and other extreme conditions.”


Based on the intended application or job site, electricians select 25-, 50- or 100-foot cords, Vidal said. The standard AWG sizes for extension cords are 16, 14, 12 and 10 AWG. The smaller the AWG number, the larger the size of the copper wire inside and the wattage rating.


However, even professionals sometimes select the wrong cord for the intended use.


“For outdoor use, an outdoor-rated cord is required,” Vidal said. “This type of product ensures things like ideal flexibility, durability, ruggedness and water resistance on a job site. Before each use, a cord should be inspected thoroughly for damage and discarded if damage is discovered. And, most important, do not plug a tool into the cord with more than the specified number of watts.”


In addition, users should look for the Underwriters Laboratories (UL) label, which is permanently attached or molded into a cord.


“Read the label for instructions and electrical ratings before use and refer to an amp-to-watt conversion table to determine the total number of watts to be used,” Vidal said. “Using a cord with a power center on a job site makes sense when running multiple tools, as long as the watts do not exceed the amps.”


The Home Depot is a large home improvement retailer based in Atlanta that markets to do-it-yourself customers and contractors. It sells extension cords from Ridgid and Husky.


Electricians most frequently purchase 14- and 12-gauge cords in 50- and 100-foot lengths, said Mike O’Conner, merchant, extension cords.


“Popular features of newer cords include lighted ends to show whether the cord has power to it,” O’Connor said. “Some cords also have locking ends so they don’t have to do things like tie a knot in them to keep them from coming unplugged.


“Multiple plugs are very handy because you can plug more than one item,” he said. “The only caution is not to overload the circuit by using too many tools at once. High-­quality cords will stay flexible and are easy to wrap and store because of the solid core jacket, rather than a jacket with filler between it and the wires.”