What type of protection is typically used for control wiring outside of panels in pneumatic systems?

In pneumatic systems, control wiring that runs outside of panels requires protection from environmental factors and potential mechanical damage. Conduit is typically used for this purpose because it provides a robust protective barrier around the wiring. It can be made from materials such as metal or plastic, both of which can withstand various conditions including moisture, chemicals, and physical impacts.

Using conduit helps ensure that the wiring remains intact and functional over time, which is crucial for the reliability of control circuits in pneumatic systems. Additionally, conduit can facilitate organized routing and support of the wiring, reducing the risk of short circuits or wear caused by friction or abrasion.

While insulation tape, direct attachment, and flexible tubing may offer some level of protection or utility in certain contexts, they do not provide the comprehensive shielding and structural support that conduit affords. Insulation tape may only insulate and not protect from external elements. Direct attachment does not safeguard against physical damage, and flexible tubing may not offer the level of durability required for long-term installations. Therefore, conduit is the most suitable choice for protecting control wiring in these applications.