Common Practices

Important Safety Recommendations: NFPA 70E

NFPA 70E Article 120 Establish an "electrically safe work condition" before working on a circuit by deenergizing it.

Create an "electrically safe work condition" by… *

(1) Identifying all power sources,

(2) Interrupting the load and disconnecting power,

(3) Visually verifying that a disconnect has opened the circuit,

(4) Locking out and tagging the circuit,

(5) Testing for voltage, and

(6) Grounding all power conductors. (used for stored or induced electrical energy and bare-hand work)

*All of these steps require the use of appropriate personnel protective equipment for shock and arc flash protection: safety glasses, voltage rated gloves, fire–resistant (FR) work clothes, arc–rated face shields, flash suits with hoods, and hearing protection.


Energy Control and Power Lockout ECPL

Whenever a worker has to be placed in a position where a part of their body may be exposed to unexpected movement, release of stored energy, electrical system energizing or potential of exposure to the flow of liquids or gasses, they have the authorization and responsibility to effectively de-energize the machinery or equipment to prevent injury or death.

Before working on any machine or equipment, it is imperative that while it is being serviced to first remove its source of electrical power. The removal of all energy sources by disconnecting and making equipment safe (inoperable) is known as energy isolation. The procedure for shutting off the power and preventing it from being energized while the work is being done is called Lockout/Tagout. This de-energized state is also referred to as creating an electrically safe work condition, abbreviated as "ESWC".


Locking out and tagging equipment does not guarantee the electrical hazards have been eliminated until the equipment is verified as being in an de-energized state. Workers must continue to perform energized electrical equipment safety practices and wear PPE appropriate for the level of incident energy until the "ESWC" is established.


OSHA 1910.147(b) defines an energy source as "Any source of electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other energy."


It is important that you know each of the OSHA recommended 8 steps for lockout/tagout in proper sequence and that you know that each person who works on equipment should have his or her own lock for preventing a piece of equipment from being started inadvertently. See OSHA's 1910.147(c)(4) Energy control procedure and 1910.147 App A . Typical minimal lockout procedures.


Click on the link below to read OSHA requirements for lockout/tagout:

OSHA FACT Sheet Lockout/Tagout

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NOTE: Every facility or plant will have its own machine and equipment lockout/tagout standards and which must be followed at all times.



Figure 1: Energy Control Power Lockout

OSHA 1910 Sequence of Lockout


(1) Notify all affected employees that servicing or maintenance is required on a machine or equipment and that the machine or equipment must be shut down and locked out to perform the servicing or maintenance.


(2) The authorized employee shall refer to the company procedure to identify the type and magnitude of the energy that the machine or equipment utilizes, shall understand the hazards of the energy, and shall know the methods to control the energy.


(3) If the machine or equipment is operating, shut it down by the normal stopping procedure (depress the stop button, open switch, close valve, etc.).


(4) De-activate the energy isolating device(s) so that the machine or equipment is isolated from the energy source(s).


(5) Lock out the energy isolating device(s) with assigned individual lock(s).


(6) Stored or residual energy (such as that in capacitors, springs, elevated machine members, rotating flywheels, hydraulic systems, and air, gas, steam, or water pressure, etc.) must be dissipated or restrained by methods such as grounding, repositioning, blocking, bleeding down, etc.


(7) Ensure that the equipment is disconnected from the energy source(s) by first checking that no personnel are exposed, then verify the isolation of the equipment by operating the push button or other normal operating control(s) or by testing to make certain the equipment will not operate.

Caution: Return operating control(s) to neutral or "off" position after verifying the isolation of the equipment.


(8) The machine or equipment is now locked out.


Restoring Equipment to Service

When the servicing or maintenance is completed and the machine or equipment is ready to return to normal operating condition, the following steps shall be taken.


(1) Check the machine or equipment and the immediate area around the machine to ensure that nonessential items have been removed and that the machine or equipment components are operationally intact.


(2) Check the work area to ensure that all employees have been safely positioned or removed from the area.


(3) Verify that the controls are in neutral.


(4) Remove the lockout devices and reenergize the machine or equipment.


Note: The removal of some forms of blocking may require reenergization of of the machine before safe removal.


(5) Notify affected employees that the servicing or maintenance is completed and the machine or equipment is ready for use.

Figure 2: OSHA 8-Step Sequence of Lockout and
5-Step Restoring Equipment to Service Procedures