When thinking about options for electrical protection, you have two choices: locking out and tagging the equipment or providing appropriate personal protective equipment (PPE).
Whether you choose lockout/tagout or PPE depends on the work, the workplace and the tasks at hand. Whenever possible, electrical workers must deenergize all circuits and equipment to be worked on by implementing appropriate lockout/tagout procedures. Only under certain conditions can employees be allowed to work on exposed energized parts.
If PPE still is required, the OSHA requirements for selecting appropriate electrical PPE are outlined in §1910.137, Electrical Protective Equipment.
However, these requirements only provide for shock protection. OSHA gives no guidance regarding flame-resistant (FR) clothing for arc flash protection. For that information, you have to consult an outside source such as the National Fire Protection Association's NFPA 70E, Standard for Electrical Safety in the Workplace.
In §1910.333(a)(1), OSHA says: “Live parts to which an employee may be exposed must be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.”
OSHA provides examples of what the agency considers increased or additional hazards and infeasibility due to equipment design or operational limitations. Increased or additional hazards include:
- Interruption of life support,
- Deactivation of emergency alarm systems,
- Shutdown of ventilation equipment in hazardous locations, and
- Removal of illumination.
An example of “infeasibility” is when circuits or equipment must be “electrically” tested. Usually, that can only be done when circuits are energized.
Locking out and tagging electrical equipment provides other advantages beyond protection from shock and arc flash hazards. It is much easier to work on electrical components without bulky PPE such as rubber gloves, leather glove protectors and FR clothing. Also, handling tools and test equipment can be a burden when wearing PPE and can actually increase the chances of an arc flash accident.
WHEN LOCKOUT/TAGOUT ISN'T AN OPTION
If your employees can't lockout and tag the electrical equipment and must work on or near energized components, OSHA provides guidance on what must done:
Only qualified employees can work on electric circuits or equipment that has not been deenergized using lockout/tagout procedures.
Qualified employees must be able to work safely on energized circuits.
The qualified employee must be familiar with the proper use of special precautionary techniques, personal protective equipment, insulating and shielding materials and insulated tools.
Employees working in areas where there are potential electrical hazards must be provided with and use electrical protective equipment that is appropriate for the specific parts of the body to be protected and for the work to be performed.
OSHA defines a qualified employee as one who has received training in and has demonstrated skills and knowledge in the construction and operation of electric equipment and installations and the hazards involved.
APPROPRIATE PPE AND OTHER EQUIPMENT
The OSHA requirements for selecting appropriate electrical PPE as outlined in §1910.137, Electrical Protective Equipment, include design and workmanship requirements, in-service care and use and testing intervals.
When employees use rubber-insulating equipment, particularly rubber gloves (the first line of defense against electric shock), it is critical that they follow OSHA's daily care and use requirements.
Protective leather gloves must be worn over the rubber gloves to provide additional protection unless you can demonstrate that the possibility of physical damage to the rubber gloves is small and you use a rubber insulating glove one class higher than required for the voltages involved.
Insulated hand tools provide an additional layer of shock protection. The insulation also protects against an arc flash hazard if the tool is mishandled or dropped.
The OSHA requirement says that when working near exposed energized conductors or circuit parts, each employee must use insulated tools or handling equipment if he or she might make contact with the conductors or parts. If the insulating capability of insulated tools or handling equipment can be damaged, the insulating material must be protected.
USING THE CORRECT EQUIPMENT
Commonly, arc flash is caused by using the wrong meter or using the right meter the wrong way. Qualified persons, those permitted to work on or near exposed energized parts, must, at a minimum, have the skills and techniques necessary to distinguish exposed live parts from other parts of electric equipment, and the skills and techniques necessary to determine the nominal voltage of exposed live parts. They also must know and understand the clearance distances specified in §1910.333(c) and the corresponding voltages to which the qualified person will be exposed.
In order to meet the above requirements and perform safe work practices, qualified employees must be thoroughly trained in using electrical test equipment.
THINK ABOUT WORK ZONES
Not only do you have to consider the work requirements for qualified electrical employees, you also have to provide appropriate protection for other employees working in the vicinity. You can do this by providing work zones where qualified employees are on one side and unqualified employees are on the other.
When setting up a work zone, you must consider the size of the zone and the method for barricading the area.
The OSHA requirements for “working space about electrical equipment” are prescribed in §1910.303. These requirements provide specific physical measurements for the space an electrician needs to work on energized equipment. The regulation states: “Sufficient access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment. Working space for equipment likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the following dimensions …”
Voltages and shock protection are considered, but the consequences of an arc flash/blast event are not. Once again, for arc flash/blast protection, you would have to reference a source such as NFPA 70E.
To barricade the area, OSHA says you can use various methods, including safety signs and tags, physical barriers or structures and attendants if needed.
Electrical work is hazardous, but it doesn't need be dangerous. Lockout/tagout provides the safest work environment, but it is not always possible. If employees must work on exposed energized equipment put your thinking cap on. You have to ensure your employees are safe when working on energized electrical systems.