Which type of conduit need not be bonded?

The type of conduit that need not be bonded is non-metallic conduit, often referred to as Electrical Nonmetallic Tubing (ENT). Non-metallic conduits are made from materials that do not conduct electricity, which means they do not need to be grounded or bonded to ensure safety against electrical faults.

Since they are not conductive, there is no risk of electrical current traveling through the conduit itself in the event of a fault, thus eliminating the requirement for bonding. In contrast, metal conduits and flexible conduits must be bonded to provide a safe path for electrical fault currents to follow, minimizing the risk of shock or fire hazards. Rigid PVC conduit, while also non-conductive, is typically treated similarly to metallic conduits in terms of bonding if it's used in specific applications, but it usually doesn't require bonding in residential applications just like ENT.