What is the purpose of a drain wire in a coaxial connector?

The purpose of a drain wire in a coaxial connector is primarily to provide a path to ground from the outer shield. In coaxial cables, the outer conductor or shield is designed to protect the inner signal-carrying conductor from external influences and to maintain the integrity of the signal being transmitted. The drain wire ensures that any unwanted electromagnetic interference or static charge that may accumulate on the shield can be safely dissipated to ground.

By grounding the outer shield through the drain wire, it effectively reduces the potential for interference to affect the inner conductor, thus maintaining a cleaner signal. This grounding also enhances safety by preventing any buildup of electrical charge that could pose risks of electric shock or damage to equipment.

The other options do not accurately describe the function of the drain wire. Increasing the signal strength is related to other factors within the cable but is not the role of the drain wire. While protecting against electromagnetic interference is a benefit of proper grounding, it doesn't directly connect to how the drain wire functions. Connecting multiple cables together pertains to a different type of installation or equipment use and is not related to the role of the drain wire within a coaxial connector.