Non-Metallic Wiring (NM)
Non-metallic wiring (NM) is the most common form of electrical wiring used in homes. Also known as cable, it is used to distribute power throughout the house, providing a safe and efficient means of supplying electricity to various appliances and lights. NM wiring is composed of two or more insulated conductors held together with a flexible sheath or jacket. The insulation protects the conductor and prevents it from coming into contact with other wires or nearby materials which could cause a short circuit or fire hazard.Romex Cable – The Most Common Type of NM Wiring
Romex cable is the most well-known name for non-metallic wiring (NM). It is a brand name for a specific type of NM cable manufactured by Southwire Company. Romex cable is widely used in homes due to its cost-effectiveness and easy installation. It is available in a variety of sizes and configurations to suit different electrical needs. The cable consists of two or more insulated conductors wrapped in a sheath made of tough, flame-retardant PVC material. The PVC sheath protects the wires from abrasion and other damage, making it ideal for use in both residential and commercial environments.Conductors – The Components of NM Wiring
Conductors are the most important components of non-metallic wiring. They are made of copper or aluminum and are responsible for transmitting electrical current from one point to another. Copper is preferred over aluminum as it is a better conductor of electricity, which means less energy is lost as heat when electricity flows through it. The conductors are insulated with a plastic material such as polyvinyl chloride (PVC) or cross-linked polyethylene (XLPE). The insulation protects the conductor from coming into contact with other wires or nearby materials, which could cause a short circuit or fire hazard.Number of Conductors in NM Wiring
The number of conductors in non-metallic wiring (NM) varies depending on the intended use. NM cable is available in a variety of sizes, each with a specific number of conductors. The most common sizes used in residential applications are 12-gauge and 14-gauge, with two or three conductors. Two conductor cables are used for light switches and electrical outlets, while three conductor cables are used for three way switches and other specialized applications.Other Types of Electrical Wiring Used in Homes
While non-metallic wiring (NM) is the most commonly used wiring in homes, there are other types of electrical wiring that can be used in certain situations. Some of these include:- Armoured cable (AC) – used in areas where the wiring is exposed to damage or extreme temperatures
- Flexible metal conduit (FMC) – used in areas where the wiring needs to be flexible or offers a conduit for wiring to be pulled through
- Electrical metallic tubing (EMT) – used in areas where the wiring needs to be encased in a metal conduit for protection against any potential hazards
Advantages of Non-Metallic Wiring in Homes
Non-metallic wiring (NM) is preferred in homes for various reasons, including:- Cost – NM cable is relatively inexpensive compared to other types of wiring
- Easy Installation – NM cable is easy to install, requiring only basic electrical knowledge or the assistance of a professional electrician for more complex installations
- Flexibility – NM cable is flexible, allowing it to be easily adjusted or routed around the home
- Safety – The plastic sheath of NM cable provides an extra layer of protection against the risk of electrical shock or fire hazards