Switch lockout

Circuit Breaker Lockout Universal Wall Switch Lockout... 

Fig. 3. Hardwired system having a PLC backup with lockout where the reset button must be pushed once the switch trips. CR = contact relay and LSHH = level switch high-high alarm "or" and "and" gates are designated as boxes.

The accidental or unexpected sudden starting of electrical equipment can cause severe injuiy or death. Before ANY inspections or repairs are made (even on the so-called low-voltage circuits) the current should be turned off at the switch box and the switch padlocked in the OFF position. At tlie same time, the switch or controls of the macliine or other equipment being locked out of service should be securely tagged to show which equipment or circuits are being worked on. Lockouts and tagouts should be removed only by the individual(s) who installed them. 

No work should be attempted until the boiler has properly cooled down, all safety and shut-off switches are in the off position, and all lockout and tagout procedures have been followed. 

Labels for all start-stop switches 8. Equipment designed to permit lockout ... 

Lock-tag-and-try procedures were developed to prevent accidents of this kind. A padlocked switch at the starter box disconnect, with the key in the mechanics pocket, prevents this type of accident. After the switch gear lockout, the mechanic should also verify the dead circuit by testing the push-button at all switches this is the try part of the lock-tag-and-try procedure. 

Locking a switch on a circuit to prevent it from being energized is a lockout. 

Design Changes 6 3 and 61f4, Bulk Outlet Temperature Lockout for The HCR "Deadman" Switch and PCCF System, All Reactors, J. L. Delchman (not yet issued ... 

In addition to overcurrent devices, other switching devices can reduce or eliminate electrical hazards. They include lockouts, interlocks, and thermal or overspeed switches. 

Some power tools have a lockout for the start switch. The idea is to prevent inadvertent operation. A tool cannot operate until a keyed switch selects the operating mode. 

In addition to overcurrent devices, certain switching devices can reduce or eliminate electrical hazards. These include interlocks, lockouts, and thermal or overspeed switches. Interlocks are switches that prevent access to an energized or dangerous location. Often attached to access doors, panels, and gates, interlocks act to shut off power to the equipment whenever these devices are opened. Probably the most commonly used and most familiar interlock... 

Maintenance employees should be qualified electricians who have been well instructed in lockout procedures. No two locks should be alike each key should fit only one lock, and only one key should be issued to each maintenance employee. If more than one employee is repairing a piece of equipment, each shovdd lock out the switch with his or her own lock and never permit anyone else to remove it. The maintenance worker should at all times be certain that he or she is not exposing other employees to danger. 

Lockout is accomplished by installing a lockout device at the power source so that equipment powered by that source cannot be operated. A lockout device is a lock, block, or chain that keeps a switch, valve, or lever in the off position. 

The device needs to meet the above definition of an energy isolating device to satisfy the standard s requirements. If an employer determines that the device does not meet the definition, then the energy supply needs to be tracked back to a disconnect switch or circuit breaker which does meet the definition. An November 10, 1999 Letter of Interpretation notes that the extent of the lockout procedures would depend on the employees activities and their exposure to the hazards. If the maintenance/repair activities will not expose employees to a certain hazard from a part of the equipment, that portion of the equipment would not need to be deenergized. The letter includes the following ... 

The motor of the chemical fume hood should be running at all times, except for maintenance. If a switch is located inside the laboratory, it should be equipped with a lockout to protect maintenance staff. 

The circuits and equipment to be worked on shall be disconnected from all electric energy sources. Control circuit devices, such as push buttons, selector switches, and interlocks, may not be used as the sole means for deenergizing circuits or equipment. Interlocks for electric equipment may not be used as a substitute for lockout and tagging procedures. 

Lockout/tagout systems are routinely used to protect workers when they are working with or close to hazardous systems. They are routinely used in conjunction with the other isolation methods. Once a switch or valve is in the correct position it is locked so that it cannot be moved, and a Do Not Operate tag is attached to it. (Valves are often chained in place, with the lock being used to secure the chain such that the valve handle cannot be moved.)... 

Tags should be used to identify locations where equipment has been altered for lockout, including valves, flanges, skillets, spectacle blinds, switches, and blocking devices. The tag should identify the person who applied it, the reason the tag was applied, and the date the tag was applied. 

Equipment must be isolated from all electrical energy sources by opening and locking all main power supplies. If the main power supply cannot be locked out, a qualified electrician must physically disconnect the equipment from the power source. Lockouts of electrical equipment are to be made at the main power supply—the use of local switches may leave other portions of the equipment energized. Once the electrical lockout is complete, an attempt should be made to start the equipment locaUy to ensure it is properly isolated before the maintenance work starts (and then all switches should be returned to their off position and tagged Do Not Operate ). 

The Lockout Planner is tasked with, proper isolation boundary points as The procedure addresses the lockout distribution panels, use of pulled air-operated valves. It also provi preparation of lockouts, including and check valves as lockout points, be used in locking out a component, sources, control power sources, all devices or control switches. 

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