When Is Lockout/Tagout Required?

Lesson Roadmap: When Lockout Applies

In this lesson you'll learn to decide when lockout is required. First, whether a task is servicing or maintenance that OSHA's lockout standard covers, including during production, when a guard comes off or a hand goes into a danger zone. Then, how to tell energy isolating devices from push buttons and selector switches. Finally, the two exceptions: cord-and-plug equipment under your exclusive control, and minor servicing that meets every condition.

Protecting Against Hazardous Energy

To prevent severe injury on the production floor, we must control the release of hazardous energy during servicing and maintenance. OSHA's standard for the control of hazardous energy, known as lockout/tagout, or LOTO for short, sets the minimum requirements for keeping you safe when machinery could unexpectedly start up. Lockout means placing a lock on an energy isolating device so the equipment cannot be operated until the lock is removed.

Defining Servicing and Maintenance

The standard covers activities where an unexpected startup or a release of stored energy could cause injury. This includes everything from installing and setting up to lubricating, cleaning, or unjamming equipment. If you must remove a guard or place your body into a danger zone during production, you are within the scope of this law.

Isolating Devices vs. Control Circuits

OSHA's lockout standard defines an energy isolating device as a mechanical device that physically prevents the transmission or release of energy, such as a manually operated electrical circuit breaker, a disconnect switch, a line valve or a block. The standard also says push buttons, selector switches and other control circuit type devices are not energy isolating devices. So lockout devices go on the energy isolating devices, never on a push button or a selector switch.

The Lockout Decision Tree

Determining if lockout is required follows a specific logic. We start by asking if the task is servicing or maintenance. If it is, we check for cord-and-plug exclusions. We then look at whether the task happens during production and if guards are being bypassed. Use this tree to decide your next move safely.

The Cord and Plug Exclusion

For cord-and-plug equipment, full lockout isn't needed if the plug is removed from the outlet. However, the plug must remain under the exclusive control of the person doing the work. If you leave the plug across the room where someone else could plug it back in, the exclusion no longer applies.

The Minor Servicing Exception

Minor tool changes, adjustments and other minor servicing during normal production are not covered if they are routine, repetitive, and integral to the use of the equipment for production. Every one of those conditions must hold, and the work must be done using alternative measures that give effective protection. If any condition is missing, the exception does not apply, and work that requires removing a guard or reaching into a danger zone is covered by the lockout standard.

Practice: Evaluating Scenarios

A technician is replacing the drive belt on a benchtop drill press that plugs into a wall outlet. They have unplugged it and kept the plug on the bench right beside them, where no one else can reach it. Type your analysis: does this require full lockout documentation and locks? Explain why based on the cord-and-plug exclusion.

Lesson Recap

OSHA's lockout standard applies to servicing and maintenance, where an unexpected start-up or a release of stored energy could injure someone. A stop button or a selector switch does not isolate a machine. A disconnect, locked off, does. Unplugged equipment is excluded only while the plug is under your exclusive control. And minor servicing is exempt only when every condition is met. Otherwise, lock out.