Course Content
NEC Chapter 3 Wiring Methods & Materials
About Lesson

Grounding and bonding are crucial safety measures in electrical systems, and different types of wiring methods have specific requirements for grounding and bonding. In this lesson, we will discuss the rules for selecting and using grounding and bonding methods for different types of wiring methods.

  1. Metal Clad (MC) Cable: MC cables consist of a metallic sheath that provides grounding and bonding. The NEC requires that the sheath be continuous and connected to the grounding system. An equipment grounding conductor (EGC) must also be installed within the cable to provide a path for fault currents.

  2. Non-metallic sheathed cable (NM): NM cables do not have a metallic sheath, so an EGC must be installed alongside the conductors to provide a path for fault currents. The EGC must be connected to the grounding system at the panelboard or service disconnect.

  3. Flexible Metal Conduit (FMC): FMC must be bonded and grounded using a grounding bushing and EGC. The EGC must be sized according to the NEC requirements and connected to the grounding system.

  4. Rigid Metal Conduit (RMC): RMC is a metallic conduit that provides both grounding and bonding. The conduit must be connected to the grounding system using grounding bushings, and an EGC must also be installed.

  5. Electrical Metallic Tubing (EMT): EMT is a metallic tubing that provides both grounding and bonding. The tubing must be connected to the grounding system using a grounding bushing, and an EGC must also be installed.

  6. PVC Conduit: PVC conduit does not provide grounding or bonding, so an EGC must be installed alongside the conductors. The EGC must be connected to the grounding system at the panelboard or service disconnect.

  7. Service Entrance Conductors: Service entrance conductors must be grounded and bonded according to the NEC requirements. The grounding conductor must be connected to the grounding electrode system, and the bonding conductor must be connected to the grounding electrode and to the equipment grounding system.

In summary, different types of wiring methods have specific rules for grounding and bonding. Metal-clad (MC) cable requires a continuous metallic sheath connected to the grounding system and an EGC installed within the cable. Non-metallic sheathed cable (NM) requires an EGC installed alongside the conductors. Flexible metal conduit (FMC), rigid metal conduit (RMC), and electrical metallic tubing (EMT) all provide grounding and bonding, and require a grounding bushing and EGC. PVC conduit requires an EGC installed alongside the conductors, and service entrance conductors must be grounded and bonded according to NEC requirements. It is essential to follow these rules to ensure a safe and compliant electrical system.

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