A sign load CANNOT exceed what percentage of the branch circuit rating?

The correct answer indicates that a sign load cannot exceed 80% of the branch circuit rating. This percentage is rooted in the National Electrical Code (NEC) guidelines, which are designed to ensure safety and prevent overheating in electrical circuits.

When calculating the allowable load on a branch circuit, the NEC takes into account the continuous nature of sign loads—meaning they often operate for extended periods. To mitigate the risk of overheating, which could lead to failure or fire hazards, it is recommended that the continuous load be limited to a maximum of 80% of the circuit’s capacity. This allows for potential variations in load and ensures that the circuit operates within a safe range.

Understanding this limit is crucial for electrical professionals to safely design and install electrical systems that include sign loads, ensuring compliance with the NEC and maintaining the safety of both the installation and its users.