Thousands of annual job-related injuries and hundreds of fatalities can be attributed to electrical hazards. Although the Occupational Safety and Health Administration (OSHA) has regulations in place to prevent these types of accidents, they still occur at an alarming rate. As a result, the National Fire Protection Association (NFPA) created 70E, Standard for Electrical Safety in the Workplace.
NFPA 70E has become the standard for the industry. Most recognize it as the comprehensive electrical safety guide to mitigate electrical hazards and make compliance with existing OSHA regulations easier. According to the NFPA, “The standard was originally developed at OSHA’s request, NFPA 70E responds to new information about the effects of arc flash, arc blast and direct current (DC) hazards, and recent developments in electrical design and personal protective equipment (PPE).”
The first edition was released in 1979 and was most recently updated in 2018. Periodic updates account for the latest technical information available. OSHA encourages those who work on or near electrical hazards to comply with the current standard. Not all electrical workers are familiar with the standard.
The standard offers guidelines for implementing administrative controls such as task planning, worker training, safe work practices and use of relevant PPE. It is intended to keep workers—qualified and unqualified—safe by preventing exposure to energized circuits or parts. NFPA 70E also helps identify hazards associated with electrical energy, shock and arc flash/blast. The standard establishes limited, restricted, prohibited and arc flash protection boundaries.
However, one of the most important topics covered by NFPA 70E is proper lockout/tagout (LOTO) procedures. Both employers and employees should be well-versed with and use the appropriate LOTO procedures. They require circuits and equipment to be placed in an electrically safe working condition through the use of LOTO. Effective use of these procedures will protect workers from electrical hazards. As a reminder, the basic steps to LOTO are the following.
Notify personnel: Ensure those working in the area are made aware that a LOTO is going to take place. This includes affected individuals and authorized employees. It is important that all affected individuals know the power will be off and where each energy source is located. This includes stored energy, as well.
Disconnect and de-energize: It is important to ensure the load is interrupted and disconnected from all energy sources.
Release stored energy: Once power is disconnected and de-energized, check for residual energy that may remain stored in the equipment or circuits. Then, discharge capacitors and short-circuit high-capacitor elements according to established procedures. Additionally, LOTO procedures for other forms of stored energy, such as hydraulic, pneumatic and mechanical should be followed.
Apply locks and/or tags: All employees must apply their lock (or tag) to all disconnecting means used to de-energize the circuit. When using a tag without a lock, another safety measure must be used.
Verification—attempt to operate: Ensure the equipment or circuit is de-energized and cannot be re-energized with the lock or tag in place. Confirm the switches or other disconnecting means can be operated with the lock or tag in place. Do not proceed until this is verified.
Verification—test for the absence of voltage: The next phase of verification is testing for the absence of voltage. The voltage detector itself must be tested before and after the equipment or circuit to complete the verification process. Then, select an appropriate voltage detector, inspect the voltage detector and wear the appropriate PPE while testing. Verification of the tester can be done by testing for voltage on a circuit, de-energizing the circuit and retesting the de-energized circuit using the same voltage tester.
Apply protective grounds: Be aware that the potential for induced voltage or other stray current exists. Apply grounds and use them rated for the maximum available fault current for the time necessary to clear the fault.
Perform work: After the LOTO procedure has been completed according the established procedures, begin work according to approved company work practices.
It is important to be familiar with all the relevant electrical safety guidelines featured in NFPA 70E. If you are interested in more information regarding NFPA 70E or purchasing a copy of the standard, visit nfpa.org. For more information regarding OSHA’s electrical regulations osha.gov. NECA also has several publications to help members better understand these safety guidelines and regulations. They are available at necanet.org.