The device that physically isolates energy at its source to prevent transmission is a(n) ____________.

• A. Energy isolation device
• B. Lockout device
• C. Tagout device
• D. Interlock

Answer: (A)

The key idea here is identifying the component that actually stops all energy from reaching the equipment by separating it from its source. The correct term is energy isolation device. This refers to any device that, when in the appropriate state, physically prevents the transmission or release of energy—electrical, hydraulic, pneumatic, thermal, or other forms—from the source to the machine. Examples include circuit breakers, disconnect switches, and valves positioned to isolate a system.

Lockout devices are used to secure these energy isolation devices in the isolated state, preventing re-energization, while tagout devices provide a warning that the equipment is not to be operated. Interlocks are mechanisms that prevent an action from occurring (like starting a machine) until safe conditions are met, but they don’t by themselves provide the primary physical isolation from the energy source.