Final answer:
When wiring is installed on the surface of interior walls, it needs to be encased in a protective rigid conduit to ensure safety and adherence to building regulations.
Step-by-step explanation:
Where wiring is run on the surface of walls, baseboards, or other interior finishes, it should be protected with a rigid covering. This is done to ensure safety and compliance with building codes. The rigid covering, often referred to as conduit, encases the wires, protecting them from physical damage and reducing the risk of electrical fires. Common materials for these coverings include metal or plastic, with each type offering different levels of protection, durability, and cost. Proper installation of the conduit is essential for the protection of the wiring and the safety of the building's occupants.