How should cables be routed and protected to comply with containment and mechanical protection requirements?

• A. In approved containment (trunking, conduit, or cable tray), maintain required distances from heat sources, avoid sharp bends, and protect from mechanical damage
• B. In free air with minimal protection to ease installation
• C. Only behind walls and under floors
• D. Only in metal conduit at all times

Answer: (A)

The basic idea is to keep cables inside approved containment and shield them from damage. Cables should run through raceways such as trunking, conduit, or cable trays that are designed to support, protect, and organize the conductors. This containment helps prevent insulation damage, reduces the chance of physical impact, and keeps cables away from things that could harm them during installation or in service. Along with containment, you must respect heat and physical stress limits: maintain required distances from heat sources so the insulation doesn’t overheat, avoid sharp bends that can crack or fatigue conductors, and provide protection against mechanical impacts with proper supports and guards. This combination ensures the installation meets safety and durability requirements.

Running cables in free air with minimal protection is not acceptable because it leaves them exposed to damage and thermal and mechanical stresses. Routing only behind walls and under floors might be possible for concealment, but it still requires proper containment and protection where noted by code. Requiring metal conduit at all times is overly restrictive and not universally necessary; many installations use a variety of approved containment methods depending on the environment and conductor type. The approved containment and protection approach is the right one because it directly addresses safety, durability, and compliance.