Thompson Rivers University
Thompson Rivers University

Lock-out Requirements

Lock-out Requirements  Locked breaker

"Lock-out" is the term applied to a system or procedure designed to control all situations where the unexpected energization, start-up, or release of stored energy of the equipment, machinery or process, would be likely to endanger or injure any personnel.

When is Lock-out" Required?
The WCB's Occupational Health and Safety Regulations require that any person (employee or student) working on a machine for maintenance must

  • secure all parts and attachments against inadvertent movement,
  • where the work will expose workers to energy sources, the hazard must be effectively controlled, and
  • the energy isolating devices must be locked out as required in these procedures

Through compliance with this lock-out procedure, any person working on a piece of machinery for any period of time, can be assured of not being injured due to accidental or inadvertent engagement of any power supply system. The intention is to ensure that the machine or equipment is placed in a "zero energy state".

The following definitions are applicable to these safe work procedures and the WCB regulations.

Assigned Lock Refers to a lock for which the worker personally controls the key.
Authorized Person Refers to a person who has been authorized by a TRU supervisor to perform the maintenance work being conducted. May refer to an employee, student or contractor.
Control Device means the device controlling the flow of power to the machinery or equipment and includes, but is not limited to: switches, circuit breakers, valves and clutches. In the case of electrical controls, it means the device controlling the flow of current to the branch circuit which supplies power to the machinery or equipment. Individual control buttons or switches in control circuits are excluded.
Control Power A term often used to refer to the energy source which powers only the control circuit for the machinery or equipment, rather than the machine or equipment itself.
Disconnect A mechanism which disconnects the machinery or equipment from the power source. (see "control device").
Hazardous Energy see "power source".
Intermediate Disconnect Refers to a control device installed between the main motor control centre [MCC] and the piece of machinery. The Intermediate disconnect is usually located near the machinery to be serviced. These devices are often used for the convenience of workers to reduce time delays which might occur by having to go to the MCC to perform lock-out functions. Where such devices are installed for the purposes of lock-out, they shall simultaneously disconnect both the motor and the motor control circuits (control power) from their sources of supply.
Lock Means a keyed padlock which will secure a control device in the "off" position and prevent it from being reactivated. Combination locks or locks using magnetic keys or bars are not acceptable.
Lock-out Is the term applied to a system or procedure designed to control all situations where the unexpected energization, start-up or release of stored energy of the equipment, machinery or process, would be likely to endanger or injure personnel. Also may be used to refer to the actual task of applying proper locks.
Lock-out Loop Refers to the loop provided on the handles of electrical disconnects, or in specialized lock-out devices for the purpose of attaching locks or multiple lock attachments.
Maintenance Means the work of keeping the machine or equipment in a safe operating condition and includes, but is not limited to:
repairing, adjusting, cleaning, lubricating and the clearing of obstructions to the normal flow of material.
Motor Control Centre (MCC) Usually refers to a centralized location of the main control devices which service the machines or equipment of a given area. These centres may be located some distance from the machinery which they serve.
Multiple Lock Attachment Means a device designed to be used to secure a control device in the "off" position and has the provision to accommodate several locks. Includes device commonly called "scissors clips", etc. May also include the use of cable lock systems, chains, etc.
Plug-in Equipment Includes electrical equipment or machinery which is not wired directly to its power source, but uses an electrical wire or cord fitted with a pronged plug on the end of the cord.
Power Source Means any source of power which provides the energy required to drive a piece of machinery or equipment and includes, but is not limited to: electrical, steam, hydraulic, water, air, mechanical radiation, and thermal forms of energy. Also includes any elevated object or part which could injure or endanger a worker in the event that it unexpectedly moved.
Tags refers to "Do Not Operate" tags or other similar label used to indicate that the device is not to be operated. The use of "Do Not Operate" tags within the TRU work environment is prohibited. The TRU Lockout Procedure must be followed.

These lock-out requirements, rules and procedures shall apply to

  1. All employees and students of TRU; and
  2. Outside contractors, sub-contractors or service personnel working on TRU equipment or machinery.


  1. It is the responsibility of all persons engaged in maintenance activities (as defined by the regulations) to know and comply with the lock-out procedures. Failure to follow these lock-out procedures is cause for disciplinary action.
  2. Supervisors and instructors are assigned the responsibility to ensure that all persons are adequately instructed in lock- out procedures and that all energy sources for equipment and machinery are deactivated and secured in the "off" position through the use of appropriate locks.
  3. In the event of a worker violating a lock-out procedure, the supervisor shall also be held accountable for the workers failure to comply.
  4. Contractors or service technicians not in the direct employ of TRU shall be responsible for providing their own locks. Under no circumstances will TRU provide locks to non-employees.


  1. Maintenance of TRU equipment or machinery shall only be conducted by persons authorized to perform such work.
  2. Contractors or outside service personnel shall sign-in with the appropriate department prior to commencing their work.

Locks and Keys

  1. Each authorized person must have their own locks issued by the department. These locks must be
    • clearly marked and
    • labelled or stamped with that persons name in order to identify the owner of the locks.
  2. Locks shall be "keyed alike" for each separate individual. No two people shall have matching keys. A sufficient number of keys will be issued by the department to each person for their own locks and the person receiving those locks shall have sufficient keys.
  3. No "extra" keys are to be retained by the Supervisor or any person other than the worker to whom the locks were assigned. No keys for lock-out locks shall be retained in the Facilities Services Department key cabinets.
  4. In the event that a persons keys are lost, the locks will be removed in accordance with the Lock Removal section of this procedure.
  5. Any person who loses their keys and/or locks must report that loss to their Supervisor immediately. Where keys are lost, if the individual does not have replacement keys, new locks will be issued or the existing locks re-keyed if possible.
  6. Persons are forbidden to remove locks belonging to another employees or student. To do so will result in disciplinary action.
  7. Under no circumstances are an individual's personal locks to be loaned or borrowed.
  8. PRIOR to removing the last lock from a control device, the person doing so is responsible to ensure that all other persons are clear of the machinery or equipment, and that it can be operated safely.
  9. When going off shift and your personal lock is still in place, your relief must put his own personal lock on BEFORE YOU REMOVE YOURS.
  10. Locks shall only be removed by the person who installed them. In the case of an emergency, see Lock Removal section of this Procedure.
  11. The use of "Do Not Start" or "Lockout" tags in place of locks is prohibited within TRU.

Multiple Lock Attachments

  1. Each authorized TRU person shall be issued with a minimum of three (3) multiple lock attachments.
  2. As an alternative to item 1, a sufficient number of multiple lock attachments shall be readily available in each MCC or other location where they might be required.
  3. When using these devices, never apply a lock to the last available opening. Always apply another multiple lock attachment.

Maintenance Department Locks

  1. Certain locks may be designated as "Maintenance Department Locks" or "Facilities Services Locks" for the purpose of securing equipment in an inoperable condition for long periods of time.
  2. These locks shall be clearly different in size, shape and colour from the type of locks used by individuals.
  3. These locks shall be numbered consecutively and the total number available be recorded.
  4. Control of these locks and their keys shall be the responsibility of the Manager, Mechanical and Electrical Services.
  5. A register (log) shall be maintained to account for the whereabouts of these locks. Where they are signed out by the appropriate supervisor, the record shall indicate who signed the lock out and indicate where the lock is being used. Upon return, each lock shall be logged back in.
  6. These locks shall not be used under any circumstance in place of personal locks.

Control Devices

  1. Some means of attaching a lock and securing the control device in an inoperable position shall be provided for all types of control devices encountered within TRU.
  2. Where the control device is of a circuit breaker type, special lock-out devices shall be attached prior to the use of a multiple lock attachment and locks.
  3. On circuit breaker panels, the use of the built-in lock on the panel cover door shall not be used for the purpose of lock-out. Doors of circuit breaker panels shall be retro-fitted with a permanent hasp or eyelets which are capable of accepting a multiple lock attachment device. Specialized lock-out devices for use on individual circuit breakers are an acceptable alternative to this.
  4. Where equipment is fitted with interlocks, those devices shall be disabled and locked out in accordance with these requirements.

Plug-in Equipment

  1. The only exception to the requirement for applying locks to control devices is when the equipment is connected to a wall or floor mounted socket or receptacle by a removable plug.
  2. Before doing any maintenance work on such equipment remove the plug from the outlet.
  3. Check that the correct plug has been removed by testing the equipment to ensure that it has been disconnected.
  4. The person performing the maintenance work must keep control over this plug at all times.
  5. Where more than one person is required to work on a piece of plug in equipment, a specialized plug lock box shall be attached to the free end of the cord and normal lock-out procedures shall be followed using multiple lock attachments.

Disengaging Power Sources

  1. Before turning off the power source, check to ensure that no one is operating the equipment. A sudden loss of power could cause an accident.
  2. If in doubt about the location of the main disconnect switch or the method of pulling it, contact the electrician on duty.
  3. An electrical disconnect shall not be disengaged (pulled) while it is under load. Such action can cause arcing or an explosion and result in injury or property damage.
  4. When disengaging an electrical disconnect be sure that the machinery or equipment is first turned off at the controls. Open the main disconnect with your left hand and face away from the panel.
  5. In larger high voltage installations only a qualified electrician should operate the main disconnect.
  6. When locking out valves, taps, or items other than electrical disconnects, the appropriate multiple lock attachment shall be placed through the lock-out loop on the control. If a lock-out loop is not available, an alternate means (i.e. chain, specialized lock-out cover, etc.) shall be used to secure the control device in an inoperable position.
  7. All accumulator tanks or reservoirs which could be holding sufficient reserve energy to operate the equipment shall be drained prior to commencing maintenance work. The drain valve shall be secured in the open position.
  8. The removal of fuses for the purpose for the sole purpose of disconnecting power is prohibited.

Locking Out - General

  1. Locking out shall be done by the first person to begin work on the machinery or equipment. That person shall be responsible for "testing" the equipment to ensure that it is not functional prior to commencing any work.
  2. Each person working on a piece of machinery or equipment, must apply their locks to lock-out all power sources. If three people are working on equipment, then three locks must be on each power source.
  3. Locking of control switches or buttons is prohibited since it is not a positive disconnect.
  4. If in doubt about lock-out rules or procedures ask your supervisor or Occupational Health and Safety Department staff.

Lock-Out Procedure
The following procedure shall be followed for all machinery or equipment, (except plug-in equipment), where maintenance is required to be performed.

  1. Shut off the machinery or equipment.
  2. Shut off the power source(s) at the control device(s).
  3. Place multiple lock attachment(s) in lock-out loop or alternate locking device. Combination locks cannot be used for this procedure.
  4. Apply personal lock(s) to multiple lock attachment(s). Each personal lock must be marked or tagged to identify the person using it.
  5. Procedures must be implemented for shift or personnel changes, including the orderly transfer of control of locked out energy isolating devices between outgoing and incoming people.
  6. Test control buttons to be sure that the power source has been disconnected.
    a. Push start button.
    b. Push stop button.
  7. Perform repairs and/or maintenance.
  8. All employee working on a machine are to remove their lock(s) as soon as they have completed their maintenance.
  9. Upon completion, clear away all tools and personnel.
  10. Replace all guards and protective devices.
  11. Ensure that everyone is clear of the machine and start the equipment to return it to normal.

Exceptions/Exemptions When it is essential to the process that the equipment remain in operation to preform maintenance related work:

  1. Only that part of the machinery which is vital to the operation shall be energised.
  2. Workers engaged in such operations must be fully authorized and trained.
  3. A seperate written safe work procedure is developed and posted adjacent to the equipment.


  1. Training in lock-out procedures shall be provided to all persons who are required to use this or similar procedures by their immediate supervisor or other trained person.
  2. If a person cannot demonstrate an understaning of the process or has violated the the procedure, additional training and supervision will be required prior to being allowed to engage in any work activity which requires the protection of lock-out.

Group Lockout Procedure

  1. If a large number of workers are working on machinery or equipment, or a large number of energy isolating devices must be locked out, the following group lockout procedure can be used.
  2. In a group lockout procedure 2 qualified persons are responsible for:
    1. independently locking out te energy isolating devices
    2. securing the keys for the locks used with personal locks or other positive sealing devices deemd acceptable by WCB
    3. completing, signing and posting a checklist that identifies the machinery or equipment components covered by the lockout.
  3. Prior to starting work, each worker must apply a personal lock to the key securing system.
  4. Workers may lock out a secondary key securing system if 2 qualified workers lock out the primary key securing system and place their keys in the secondary system.
  5. When work is completed, people remove their keys from the key securing system.
  6. When it is determined that it is safe to end the group lockout, the 2 qualified persons identified in subsection 2 remove their locks.
  7. This procedure must be posted where the system is in use.

Lock Removal Procedure
Removing another employee's lock is a serious matter and is prohibited except in the case of an emergency and only when this procedure has been followed:

  1. The area supervisor shall be informed that a lock needs to be removed and that the person assigned the lock cannot be located;
  2. The area supervisor will make every effort to contact the lock owner and document these attempts on the attached checklist;
  3. The area supervisor shall then contact the chairperson (for instructional staff), or the appropriate Manager (for non-instructional staff) to request their attendance at the area inspection and lock removal.
  4. An alternate to either of the above persons would be to contact Occupational Health and Safety and request their attendance.
  5. At least one worker representative will be present during the inspection of the area and lock removal.
  6. If the person cannot be located and the area in question has been inspected and is clear of any hazards to anyone, the lock may be cut off.

Locks Not Required

  1. Locks are not required if the energy isolating device is under the direct control of a single worker at all times while working on the machinery or equipment and,
  2. A tool, machine or piece of equipment which receives power through a readily disconnected supply such as an electrical cord or quick release air or hydraulic line is disconnected from its power supply and its connection is kept under the immediate control of the worker at all times while the work is being completed.