What does “junction box fill” refer to?

"Junction box fill" specifically refers to the volume of conductors, devices, and fittings allowed in a junction box. This concept is crucial for ensuring electrical safety and compliance with applicable codes, as overfilling a junction box can lead to heat buildup, reduced functionality, and even potential fire hazards. The National Electrical Code (NEC) outlines guidelines on how to calculate the fill capacity of a junction box based on the size and type of conductors and devices.

Understanding junction box fill helps electricians determine the appropriate box size and type for any installation to maintain safety and reliability in electrical circuits. Proper box fill ensures that all components fit securely and safely, allowing for adequate airflow and minimizing electrical faults.