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DOE/EH-0328 --- Issue No. 93-06 --- 07/93
Labeling Errors Cause Accidents
Every month in at least one Department of Energy (DOE) facility, the
lights go out, the power to an electrical system is accidently shut off,
or a worker experiences a near-miss incident. These are just some of the
problems caused by labeling errors on electrical equipment at DOE sites.
The three most common labeling problems follow:
- No label
- Inadequate label
- Incorrect label
COULD THE FOLLOWING INCIDENTS HAPPEN AT YOUR SITE?
- A mechanic tracing electrical wires connected to emergency cutoff
power switches traced one wire to an unlabeled, covered switch.
When he opened the cover, the building's entire electrical system shut down.
- Electricians were testing an unlabeled step-up transformer. They
assumed both sides were 480 volts. When they attempted to test the secondary
side, it arced violently toward the volt meter. It was actually 1760 volts.
- Two electricians were troubleshooting a voltage problem on an
inadequately labeled switchgear. Because the labeling was
incomplete, the lead electrician inadvertently opened the station
service disconnect, which could not safely interrupt the load
current. It arced & singed the electrician's arm, causing him to
fall backward & hit his head.
- A craft person performing a zero energy check before tagging out a
breaker found that it was still energized. The breaker was a small,
dark-colored, molded-case breaker with ON/OFF indicators molded into
the toggle, which makes them hard to read. The worker who performed
the lockout thought he had turned the breaker off when he had
actually turned it on.
- An electrician removed a fuse labeled FU-5 as specified in his work
package, but he removed it from the Control Room instead of the
Equipment Room because this site did not have location-specific
labels for all components. His action shut down the computer
control system, which in turn shut down the mixer module ventilation
system.
- The east exhaust fan at one DOE site was locked & tagged out. As
workers were removing the housing bolts prior to dismantling the
fan, another worker attempted to activate the east fan to ensure
that it was deenergized. The fan turned on. The label for the east
fan should have been on the west fan and vice versa.
- Power to the cooling towers of one facility was shut down when a
worker opened the wrong circuit breaker because it was mislabeled.
- Mislabeled wires led an electrician to hook up two hot wires instead
of one hot wire and one neutral wire. Later, when he tried to plug
in an extension cord near the receptacle, an arc occurred and the
worker experienced a nonfatal shock.
WHAT CAN YOU DO TO PROTECT YOUR WORKERS?
DOE Order 5480.19, Conduct of Operations Requirements for DOE Facilities,
requires labels for electrical equipment, such as compressors, switches,
circuit breakers, fuse blocks and busses, motor control systems, fire
protection systems, and many other components. In addition, the National
Electrical Code, 1993 edition, is specific about labeling for all types of
electrical components, such as transformers, junction boxes, cable
assemblies, etc. Use these regulations as a guide to proper labeling
practices.
SUPERVISORS
- Perform a walkdown of your assigned area of responsibility and check
every electrical component, box, panel, etc., for missing labels.
- Compare electrical drawings, procedures, instrument diagrams, etc.,
with the labels on components to ensure that they match. If they do
not match, determine which identification is correct and make the
necessary changes to establish a match.
- Look for potential areas of misunderstanding, such as the molded-
case breakers previously mentioned, and add labels to make the
ON/OFF positions clear.
- Ensure that your facility uses an alphanumeric system to identify
every component with a unique identifier.
- Ensure that labels are clear and easy to read. Consider using a
color coding system to enable faster identification of key
electrical systems.
- Include all vital information on the label. For example, a label
should say more than just "motor," it should say "motor, water pump,
part of emergency fire system."
WORKERS
- Do not work on an unlabeled item, such as a transformer or
electrical box, unless you have checked the diagrams first.
- Report all unlabeled components to your supervisor.
- Check for live or stored energy before starting work on any locked
out/tagged out electrical system.
- Do not lockout/tagout an electrical item unless you are sure it is
the one identified on your work package. Stop work & ask your
supervisor before proceeding, or you could shut down power to your
whole building.
Labels are an important part of an effective electrical safety program.
It is the responsibility of both supervisors and workers to ensure that
all equipment is labeled properly.
This Safety Note is one in a series of publications issued by EH to share
occupational safety information throughout the DOE complex. To be added
to the Distribution List or to obtain copies of the publication, call
(615)576-7548. For additional information regarding the publications,
call Barbara Bowers, Safety Performance Indicator Division, Office of
Environment, Safety and Health, U.S. Department of Energy, Washington, DC
20585, (301)903-3016.
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