RCO Training – Mechanical Practice Test

Lockout/tagout hinges on controlling all sources of energy so a machine can be worked on safely without the risk of unexpected startup or energy release. The strongest sequence starts with identifying every energy source the equipment could have—electrical, hydraulic, pneumatic, thermal, mechanical, or chemical—so no potential energy is overlooked. Then the energy is de-energized to remove power, and the system is isolated to ensure energy cannot flow back in. Applying lockout or tagout devices provides a physical and visible barrier that prevents anyone from re-energizing the equipment. After that, you verify zero energy to confirm there is truly no residual or stored energy present before you begin maintenance. Only once this verification is complete do you perform the work. When maintenance is finished, remove tools and confirm the area is safe, then remove the lockout/tagout devices and re-energize only after clearance. This full sequence is essential because skipping steps or performing them out of order can leave someone exposed to unexpected startup or stored energy.