Is It Safe to Make Your Own Extension Cord with Romex?

Using Romex NM cable to make an extension cord is not only not recommended but also typically not compliant with electrical codes. This guide will explore the reasons why this practice is discouraged and provide a cautionary tale from a former 'redneck' DIY enthusiast on how to do it safely, if you must.

Intended Use and Safety

Romex (Non-Metallic Sheathed Cable) is designed for permanent wiring within walls and is not intended for portable applications like extension cords. Its construction lacks the necessary flexibility and durability for frequent movement. Extension cords, on the other hand, are specifically designed with appropriate insulation and protection for outdoor use or for movement. Romex does not have the same protective features, making it less safe for temporary connections.

Code Compliance and Safety Hazards

The majority of electrical codes, including the National Electrical Code (NEC) in the United States, do not permit the use of Romex for extension cords. Using Romex in this way could lead to violations and safety hazards. For instance, if you improperly coil or bend an extension cord made from Romex, you risk damaging the insulation and potentially exposing live wires, which can result in electrical shock or even a fire.

Risk of Damage and Durability

Romex is not as durable as proper extension cord materials. It can be damaged easily, leading to exposed wires and an increased risk of shock or fire. If you must make your own extension cord, it is crucial to use materials designed for this purpose.

Purchasing a High-Quality Extension Cord

The safest option is to purchase a high-quality extension cord that is specifically designed for that purpose. These cords are built to withstand repeated use, provide adequate insulation, and are suitable for both indoor and outdoor applications. If you require a custom length, consider using proper extension cord components and ensuring they meet safety standards.

A Cautionary Tale from a Redneck DIY Enthusiast

While attempting to do things the 'right way' is ideal, sometimes DIYers must resort to unconventional methods. A former 'redneck' tells a story of using Romex to create an extension cord. Here's how they did it safely:

Buy a High-Quality Vinyl Tube: Find a vinyl tube with fiberglass reinforcement that is slightly larger than the Romex. Slightly larger tubes can add some flexibility and strength. Lubricate the Romex: Lubricate the Romex with conduit wire lube to make the cable sliding through the tube easier. Slide the Romex Through: Pull the Romex through the vinyl tube, leaving about 8 inches at either end of the cord. Clamp the Ends: Use a 4-inch metal box or a clamp to secure the ends of the cord. Ensure the metal box or clamp is tightly secured to prevent any movement that could damage the insulation. Install Safety Components: Place a Ground Fault Circuit Interrupter (GFCI) on one end and a USB outlet on the other. Use a metal cover plate to protect the connections. Ensure both ends of the cord are well-protected and dry, especially if used outdoors. Double the Vinyl Tube: If you are concerned about the quality or strength of the vinyl tubes, consider using two tubes with a slightly larger diameter and doubling them up. This will provide even more strength and protection.

Caution: Keep in mind that connecting the Romex to a GFCI receptacle follows a specific procedure that should not be attempted without proper knowledge. Misconnecting or attempting to bypass safety features can lead to serious hazards. Always consult with a professional electrician if you are unsure about any part of the process.

While this DIY method worked for the maker in the short term, it is strongly recommended to use professionally manufactured extension cords for safety and compliance. If you're truly concerned about cost, consider using high-quality materials and following strict safety guidelines to minimize potential risks.