What is the minimum size of the bonding conductor used for bonding metal parts of signs and outline lighting systems?

The minimum size of the bonding conductor used for bonding metal parts of signs and outline lighting systems is indeed 14 AWG. This requirement is based on safety standards established by the National Electrical Code (NEC), which mandates that bonding conductors must be adequately sized to ensure safe and effective grounding of electrical components.

A bonding conductor is critical for creating a path for fault currents, thus minimizing the risk of electric shock or fire hazards. The selection of 14 AWG is based on its ability to safely carry fault currents while being manageable for installation. Larger sizes, such as 10 AWG or 12 AWG, while safe, are typically reserved for applications requiring greater current carrying capacity, whereas smaller sizes like 16 AWG may not meet the necessary requirements for bonding safety in these systems.

Thus, 14 AWG provides a balance of safety, compliance with code requirements, and practicality in the context of bonding for signs and lighting systems.