Above-ground service-entrance cables that are subject to physical damage must be protected by what type of conduit?

The correct choice for protecting above-ground service-entrance cables that are subject to physical damage is Schedule 80 PVC conduit. This type of conduit is designed to provide additional durability and impact resistance compared to thinner conduits. It features a thicker wall than Schedule 40 PVC, making it suitable for applications where the cables may be exposed to physical impacts, such as from vehicles, machinery, or other objects.

When cables are placed in areas where they could be hit or damaged, ensuring they are encased in a robust conduit prevents wear and tear, as well as potential electrical hazards. Schedule 80 PVC conduit is also rated for both indoor and outdoor use, making it versatile for various installation environments.

Other options such as Schedule 20 and Schedule 40 PVC conduits are not suitable because they do not provide the same level of protection against physical damage, as their wall thickness is insufficient for high-risk areas. Schedule 100 PVC conduit is also not standard in most applications and is less common for service-entrance use. Thus, choosing Schedule 80 PVC conduit is the most appropriate and safest choice for the protection of above-ground service-entrance cables.