When might a bushing be required on a conduit installation?

A bushing is typically required in conduit installations when the conduit passes through combustible materials. This requirement is rooted in safety standards that aim to prevent potential fires and ensure the integrity of electrical installations. The bushing acts as a protective barrier, providing support to the conduit and preventing the sharp edges of conduit openings from damaging the wiring or conductors that could lead to electrical faults or increased risk of combustion in flammable situations.

When dealing with combustible materials, proper protection is crucial, as it helps maintain a safe installation by ensuring that no bare wires are exposed and that the conduit remains intact throughout its use. This proactive measure is essential in reducing fire hazards and ensuring compliance with electrical codes.

In contrast, the other options do not inherently necessitate the use of bushings. For example, the material of the conduit or its diameter doesn't dictate the need for a bushing strictly based on those factors alone. Similarly, although larger gauge conductors may require careful consideration during installation, they do not inherently trigger the requirement for bushings unless related to the specific context of the installation through combustible materials. Thus, understanding the application of bushings is vital in maintaining both safety and adherence to installation standards within electrical work.