A journeyman electrician with more than 25 years of experience found out the hard way that decades spent on the job doesn't necessarily make you immune to its hazards. The following accident occurred when the electrician and his apprentice were removing a circuit from a 480V, 600A main breaker panelboard in the electrical room of a large public building. Although the breaker, which supplied power to the entire building, was in the off position, the conductors running into the top of the breaker were still energized. The journeyman was in the process of removing a circuit from the upper left-hand of the enclosure while the apprentice was standing on a ladder 4 to 5 feet to the left, manually supporting the conduit that held the electric wires. The ground wire being removed was still connected at its other terminal. Electrical tape had not been used to insulate this wire or the phase wires. In addition, shielding material was not used to protect the exposed energized conductors entering the main breaker.
At some point, the ground wire apparently contacted the energized terminals on the main circuit breaker. According to the apprentice, a large flash and loud noise occurred, followed by two more explosive noises. Seeing that the journeyman's synthetic clothing was in flames, the apprentice used his hands to extinguish the fire, burning himself in the process. He immediately removed the journeyman from the smoke-filled room and called 911.
The journeyman sustained second- and third-degree burns over approximately 50% of his body. In addition to requiring surgery for removal of destroyed skin and restorative skin grafts, the electrician spent nearly a year undergoing physical therapy. The apprentice was treated for second-degree burns.
To prevent similar injuries, the following steps are recommended:
Establish an electrically safe work environment whenever possible. This includes de-energizing, lockout/tagout of disconnecting devices, grounding to protect against stored or induced electrical energy, and testing to ensure the absence of voltage.
If work must be performed on energized equipment, ensure it is performed under an effective energized work policy that meets all requirements set forth in NFPA 70E, 130.1-130.7 (2004). This standard outlines the requirements of an energized electrical work permit with an acceptable justification for the live work to be performed as well as a description of the safe work practices to be employed.
Electricians should wear flame-resistant clothing and appropriate PPE for arc flash/blast exposure.
Electrical panels should be updated to ensure compliance with current codes and safety requirements.
Editor's Note: This electrical safety lesson is based on SHARP Report #85-2-2006, developed by the Safety & Health Assessment & Research for Prevention (SHARP) Program at the Washington State Department of Labor and Industries.