In Lockout Tagout, which step requires disconnecting all primary energy sources?

• A. Address all secondary sources
• B. Disconnect all primary energy sources
• C. Verify the lockout
• D. Keep it in force during shift change

Answer: (B)

Lockout/tagout is about preventing unexpected startup by physically isolating a machine from its energy sources and securing that isolation with a lock and tag. The step that requires disconnecting all primary energy sources is the isolation action—you physically separate the equipment from the main power supply so there is no path for energy to reach it. This is the essential action that makes the subsequent lockout effective. After isolation, you verify that energy is actually off and then keep the lockout in place, even through shift changes, until work is finished. Addressing secondary or stored energy is important, but it does not achieve de-energization on its own without first disconnecting the primary sources.