The total rating of utilization equipment fastened in place, other than luminaires, shall not exceed what percentage of a multiple outlet branch circuit rating?

The correct choice indicates that the total rating of utilization equipment fastened in place, other than luminaires, must not exceed 50% of the rating of a multiple outlet branch circuit. This requirement is established to ensure safety and proper load management in electrical systems.

By limiting the total equipment rating to 50%, it helps to prevent overheating and potential fire hazards that could arise from overloading the circuit. The reasoning behind this percentage involves considering the factor of how much load can be safely managed without exceeding the circuit's capacity. This is particularly important when dealing with multiple devices that may draw power simultaneously, leading to a more reliable and safe installation of electrical equipment.

In practice, this guideline helps electricians and builders to make informed decisions regarding the placement and connection of electrical devices, ensuring they remain within safe operating parameters. Proper adherence to these limits is crucial for the longevity of both the electrical infrastructure and the devices connected.