Final answer:
The minimum size of a pendant conductor supporting mogul or medium base screw shell lamp holders is typically 18 AWG for conductors up to 20 inches in length, and 16 AWG for conductors over 20 inches, referencing the standards set by the National Electrical Code.
Step-by-step explanation:
The minimum size of pendant conductor supporting mogul or medium base screw shell lamp holders is specified in the National Electrical Code (NEC). The NEC stipulates that conductors must be of a sufficient size to handle the electrical load that they will carry, to prevent overheating and potential fire hazards. Specifically for lighting fixtures, conductors for pendant lamps and similar hanging fixtures should not be smaller than 18 AWG for conductors up to 20 inches in length, and not smaller than 16 AWG for conductors over 20 inches in length, unless they are part of a cable assembly or a cord that has been evaluated for such use.
It’s important to always refer to the latest edition of the NEC or consult a professional electrician to ensure compliance with all applicable safety codes and regulations.