What must be provided between all entries when using nonmetallic boxes with metal raceways or metal-armored cables?

When using nonmetallic boxes in conjunction with metal raceways or metal-armored cables, bonding means must be provided between all entries to ensure electrical continuity and safety. This requirement is essential because nonmetallic boxes do not naturally bond to metal systems, which could otherwise lead to potential shock or fire hazards due to improper grounding.

Bonding ensures that all metal components within an electrical installation are at the same electrical potential, reducing the risk of stray currents that might flow through the surface of the equipment. This is particularly crucial in environments where there are multiple conductive paths. Hence, using bonding means between the nonmetallic boxes and metal raceways ensures a secure and safe connection, complying with the NEC requirements.

Other choices such as insulation, grounding, and temporary supports do not directly address the relationship between nonmetallic boxes and metal enclosures. While insulation and grounding are important in electrical systems, they serve different purposes separate from the bonding requirement specifically needed to ensure proper electrical continuity between dissimilar materials. Temporary supports are irrelevant in the context of electrical safety and bonding. Thus, bonding means is the specific necessity when mixing nonmetallic and metallic components in electrical installations.