In a hazardous classified location, how must flexible metal conduit be bonded?

In a hazardous classified location, bonding of flexible metal conduit is critical to ensure safety and prevent potential electrical hazards. The correct approach is to use an external bonding jumper, which provides a reliable means of establishing a continuous electrical connection with the ground. This is essential in environments where flammable gases or vapors may be present, as it minimizes the risk of electrical arcing or sparks leading to ignition.

Using an external bonding jumper enhances the effectiveness of the bonding system because it ensures that the entire run of conduit is effectively connected to the grounding system, thus providing added protection. This requirement is in line with established electrical codes that govern installations in hazardous locations to enhance safety and reliability.

While flexible metal conduit has conductive properties, relying solely on it to serve as an equipment grounding conductor, bonding only at equipment, or assuming that it does not require bonding altogether would not meet the necessary safety standards in hazardous environments. This is why the option regarding the necessity of an external bonding jumper is the correct and safe practice.