Arc flash hazards should be approached in a systematic, consistent manner for maximum safety. Everyone involved in a facility's electrical system--management, engineers, technicians, and outside contractors--has a role to play in insuring a company and its employees against the dangers of arc flash.
There is only one way to completely avoid the risk of arc flash--never perform work on energized equipment. Whenever possible, equipment should be placed in an electrically safe work condition by following the steps outlined in NFPA 70E.
In some situations, such as when testing equipment, or when a circuit provides power for ventilation systems, de-energizing equipment is not a possibility. In these cases, it is important to follow careful and systematic safety procedures for work on live equipment.
Protect workers from the dangers of arc flash by displaying custom-designed, NFPA/OSHA compliant labels and signs. Print arc flash hazard labels as small as two inches with the DuraLabel 2000 or as big as nine-inches with the DuraLabel 9000. Need to print die-cut labels, two-color vinyl tapes or blank vinyl tapes? DuraLabel has the supplies you need to quickly and conveniently print required electrical shock and arc flash warning labels.
Common tasks requiring work on live equipment include operating disconnects and breakers, racking breakers, opening equipment doors for inspection, removing panels, and measuring voltage. Since equipment must be assumed to be energized until proven otherwise, even measuring voltage to confirm de-energization is considered live work.
If it is necessary to work on live equipment, a number of steps can be taken to minimize the risk of injury.
The first step in managing arc flash hazards is to perform a facility-wide arc flash hazard analysis. This engineering study will, among other things, identify equipment that should be labeled (see below), calculate risk/hazard levels for PPE, and determine protection boundaries. The arc flash hazard analysis is the cornerstone for safe work on live equipment.
The NEC and NFPA 70E both require warning labels on equipment that poses an arc flash hazard. These labels must include either the incident energy or the required PPE, but can include more information at the company's discretion. Establish a standard design for warning labels throughout a facility.
Whenever work must be done on energized equipment, workers should obtain a written live work permit. Requiring live work permits helps to guard against unnecessary live work, and ensures that hazards are properly identified. A live work permit should include the equipment to be worked on, a description of the work to be done and why it is necessary, the name of the worker, and the results of a hazard analysis for the work, including protection boundaries.
Regular, careful maintenance of electrical equipment is an important but often overlooked part of an arc flash safety program. Corrosion, dust, and insulation failures all increase the chances of arc flash incidents. Improper installation of equipment or lack of adequate upcurrent protective devices can greatly affect the severity of an arc flash. Ideally, electrical systems should be modified or even designed from the ground up to ensure maximum safety from electric hazards.
Training is a critical part of an electrical safety program. All employees should be trained on arc flash hazards and how to avoid them. In addition, electrical workers must receive training on safe work practices specific to the equipment they are working on, as well as general training on proper use of PPE, protection boundaries, and so forth. Document all on-the-job training--lack of documented safety training is a leading source of OSHA citations. Training records should include the date, employees who received the training, topics covered, and trainee signatures or initials.
Having the proper tools can reduce the risk of arc flash, and is mandated by NFPA 70E. All tools used to work on live equipment must be non-conductive. Voltmeters must be insulated and rated for the equipment voltage. Long-handled tools can reduce risk of injury by increasing the working distance. For particularly high-risk procedures such as racking breakers, remote systems may be appropriate.
Personal Protective Equipment is the last line of defense against arc flash injuries. It is the only method of defense that does not rely on preventing an arc flash incident, but on protecting workers if an incident occurs. PPE includes cotton or flame-resistant clothing, gloves, insulated blankets, and face shields. PPE must be worn at all times when within the Flash Protection Boundary. The proper level of PPE depends on the available incident energy and other characteristics of the equipment. More information about PPE can be found on our arc flash PPE page.
If, despite every precaution, an arc flash incident occurs and workers are injured, it is important that rescue and treatment are performed in a manner that does not risk further injury, either to the injured worker or others.