A drain wire makes electrical contact with the cable shield, giving interference and unwanted electrical noise a path to ground instead of coupling into the signal or control conductors. Connect the shield and drain wire according to the equipment manufacturer’s instructions, often at one designated grounding point, to help reduce noise while limiting ground-loop concerns.

Choose 18-gauge or 22-gauge drain wire cable based on the connected equipment’s specifications and the run’s power and signal requirements, with 18-gauge options supporting line-level audio and control applications and 22-gauge options fitting lower-current control wiring. Select a two-conductor shielded configuration for basic audio or control, a two-pair shielded configuration for separate audio, control, or DMX lighting signals, or a bundled cable with additional unshielded conductors for lighting, shade, keypad, and automation systems.

When installing drain wire cables, match the conductor count, gauge, shielding, drain wire, and system requirements to the application, such as line-level audio, control, lighting, or automation. For residential, commercial, or outdoor systems, verify the cable’s voltage, temperature, fire, and listing requirements, and plan routing, shielding, drain-wire termination, and grounding according to the equipment instructions and local code.

Select a drain wire cable based on the system’s voltage requirements and the installation temperature range, since available constructions support low-voltage use below 80 V and may list ratings up to 300 V or 600 V, with operating ranges that vary by cable. For installations where fire performance matters, look for the applicable CL3 and FT4 ratings, and verify the cable’s listing against local code and project requirements.