What is the minimum curve radius of the inner edge of a 90° bend for nonmetallic-sheathed cable in relation to its diameter?

The minimum curve radius of the inner edge of a 90° bend for nonmetallic-sheathed cable is determined by the need to prevent damage to the cable's insulation and conductor. It is essential for maintaining the integrity and performance of the cable. When designing installations, adhering to these guidelines helps ensure that the cables do not suffer from excessive stress, which could lead to shorts or failures over time.

The correct choice indicates that the minimum radius should be five times the diameter of the cable. This ratio provides ample space for the cable to bend without risk of pinching or compromising the materials. A radius smaller than this would not allow the cable to maintain its structural integrity.

The requirement for a minimum curvature of five times the cable diameter balances flexibility with safety, ensuring that the cables can be routed in tight spaces while still functioning reliably. Employing this standard helps to protect investments in electrical installations and promotes longevity and safety in electrical systems.