What type of conduit may be used above the 10 ft minimum?

The correct answer regarding conduit types that can be used above a minimum height of 10 ft is Schedule 40. Schedule 40 conduit is designed to handle a variety of environmental conditions and mechanical loads, making it a suitable choice for overhead installations. It provides adequate strength and durability for electrical wiring in applications where low weight and moderate resistance to physical impact are required.

Schedule 40 is commonly specified in electrical codes for use in both indoor and outdoor applications, including locations that might require support at higher elevations. This type of conduit is also cost-effective and widely available, which contributes to its popularity among linemen and electrical contractors.

In essence, Schedule 40 meets the requirements for structural integrity and safety standards, making it appropriate for use above 10 ft, whereas other schedules may not be suitable due to considerations like thickness, strength, or intended application.