February 2, 2001

Background:

In late December, 2000, the Facilities Electrical Shop responded to a request to disable circuits in an electrical raceway at approximately 2:00 pm on a Friday afternoon. The responding electrician discovered that turning off the panel supplying power to this electrical system was not feasible because it also fed power to other areas of the building. In an effort to accommodate the requestor, the electrician turned off only those circuits that appeared to be routed from the panel through the electrical raceway. He then offered to verify that there was no remaining electrical hazard, but as it was already the end of the workday, both parties agreed that this could be resumed the following Monday morning.

When the system was tested that Monday, it was discovered that several circuits were still energized and that this condition had existed over the entire weekend, thus posing a hazard to anyone who may have come in contact with the circuits.

Analysis:

This illustrates the importance of following proper Lockout/Tagout (LO/TO) procedures. LO/TO is required whenever service, maintenance, or modification is being performed on equipment in which the unexpected energization or release of stored energy could cause injury to people or result in damage to equipment. All sources of hazardous energy must be shut off and secured and LO/TO must be performed by each and every person who works on the equipment. In this particular case, to initiate, but not complete the LO/TO process created the possibility of an individual coming in contact with hazardous electrical energy (208 volts )

Corrective Actions/Suggestions:

While accommodating customers is important, they need to be informed when there is not enough time to complete the task safely. In this case, the work should have been postponed until the following Monday as it is important to start and complete the task with no gaps. Once LO/TO is started it must be completed. If this is not possible, then the system must be disabled to ensure that there is no risk to personnel.

Further Information

For further information on this incident please contact Tom Caronna the LBNL Electrical Safety Engineer at extension 4314.

Pub 3000, Chapter 18, Lockout/Tagout may be consulted for additional information (http://www.lbl.gov/ehs/pub3000/CH18.html).