Can Romex Be Installed Outside? What You Need to Know

As a homeowner, understanding the basics when it comes to home electrical wiring is important. If you’re planning to do any work on your house’s wiring, you may be wondering if Romex wiring can be used outside. Knowing the different standards and what you can use for outdoor wiring can help ensure that you complete the job correctly while keeping yourself and your family safe.

Romex, or NM-B cable, is a popular type of non-metallic sheathed wiring that is most commonly used in residential and light commercial buildings. It is an essential material for home electrical wiring and is composed of two or more insulated conductors in a protective jacket. However, Romex can only be used indoors and is not suitable for outdoor installations.

Different Types of Romex Wiring

Romex wiring comes in two main types; single-strand (NM-B) and multi-strand (NM-B). Single-strand Romex cable is composed of a single copper conductor with a plastic insulation around it. This type of wiring is usually used in shorter runs between outlets and switches, and cannot be used in areas where the cable may come into contact with water. Multi-strand Romex cable has multiple copper conductors surrounded by a single plastic casing and is typically used in longer runs between outlets, switches, and fixtures.

Why Romex Is Not Suitable For Outdoor Installation

Romex wiring is designed for use in heated and air-conditioned environments. When exposed to extreme temperatures, consistent moisture, and UV rays, the cables deteriorate rapidly, becoming brittle and dangerous. In addition, the plastic outer casing of Romex wiring is not rated for direct burial and may overheat if installed too close to other wiring. As such, Romex wiring must not be used for outdoor installations.

What Type Of Wiring Should You Use For Outdoor Installations?

When installing outdoor wiring, it is important to use the proper type of wiring, depending on the application. The National Electrical Code (NEC) requires that wiring used outdoors should be rated for wet locations, such as UF-B cable. This type of cable is designed specifically for outdoor use and is rated for direct burial and exposure to sun, rain, and snow. UF-B cable is constructed with multiple conductors surrounded by a tough, waterproof jacket and is highly resistant to ultraviolet radiation, temperature extremes, and mechanical damage.

Importance Of Professional Installation

Regardless of the type of wiring you choose for your project, it is important to have the installation performed by a qualified electrician. An experienced electrician will know the correct type of wiring to use and can help ensure that the installation is performed safely and correctly. This can help save you time and money in the long run, as well as prevent safety hazards.

Conclusion

So can Romex be installed outside? The short answer is no. Romex wiring is not suitable for outdoor installations due to its construction and ratings. Before you begin working on any electrical projects, you should understand the various types of wiring and their ratings, so you can complete the job correctly and safely. It is also important to make sure that any work is performed by a qualified electrician.

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