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Chapter Seven - Electrical
Safety
and Lock-out/Tag-out
Case Studies 1:
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A worker was changing the bulb in a light fixture that had
been incorrectly wired (polarity was reversed). He
inadvertently touched the metal base of the bulb while it was in
contact with the socket. He received a severe shock and
later died in the hospital. -
On July 29, 1985, a 29 year old welder
was electrocuted when he inserted the "male" end of an electrical
plug on a portable arc welder into a broken "female" connector of
an extension cord. As in the previous case, the victim
inserted the ground prong of the welder cord 90 degrees clockwise
away from the appropriate ground terminal of the extension cord,
and the metal casing of the welder connector became energized.
It appeared that the connector on the extension cord had been
damaged by everyday use or abuse (being thrown down on and dragged
across concrete floors, being run over by industrial equipment,
etc.)
Conclusions:
Caution should be used around ALL
electrical circuits and equipment. The Potential for
electric shock should never be underestimated. Employers and
other groups should regularly emphasize the safe use of
electricity in the workplace. Continuous efforts must be
made to prevent electrical injuries and death due to damaged
receptacles and connectors.
Case Studies 2:
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Successful Resuscitation - A 30 year old
construction worker was working on a fire escape in a building
being renovated. Another worker handed the victim a metal
pipe, and he was holding it with both hands when it contacted a
nearby high voltage line, completing a path-to-ground. The
worker instantly collapsed from this contact with electrical
energy. Approximately 4 minutes after he collapsed, the fire
department rescue squad arrived and began CPR. Within 6
minutes, a paramedic unit was on the scene providing
defibrillation and other ACLS measures. They were able to
establish a heartbeat and pulse, but the individual continued to
require respiratory support during transport to the hospital.
He regained consciousness and was discharged within two weeks.
He did have to return for further medical care for burns he
received on his hands (current entrance) and buttocks (current
exit). -
Unsuccessful Resuscitation - An 18 year
old male restaurant worker contacted electrical energy when he
kneeled to plug a portable electric toaster into a 100-120 V/20
amp floor outlet. After a scream was heard, the victim was
found convulsing on the damp floor, with one hand on the plug and
the other on the receptacle box. The assistant manager went
to the electrical panel, but was unable to locate the appropriate
circuit breaker. A coworker attempting to take the victim's
pulse received an electrical shock, but was not injured.
After telephoning the emergency medical service, the assistant
manager returned to the panel and de-energized all of the circuits
(3 to 8 minutes after the worker contacted electrical energy).
The injured worker was covered with a coat to "keep him warm".
After about 5 minutes, another call was placed to the emergency
squad, and the assistant manager yelled for an off-duty employee
who lived in an apartment across the lot, who came and began CPR.
The emergency service was on the scene 10 minutes after receiving
the first call. ACLS measures were available but the
resuscitation was unsuccessful and the worker was pronounced "dead
on arrival" at the local hospital. The exact time span
between the worker contacting electrical energy and the beginning
of CPR is unknown but it is reasonable to assume that it was
longer than 4 to 6 minutes. Paramedics with ACLS capability
arrived 10 minutes after receiving the call, but more than 10
minutes after the accident occurred.
Conclusions:
In Case #1, basic life support was begun within
4 minutes by the fire department rescue squad who happened to be
stationed nearby. They were experienced and had up-to-date
knowledge in CPR techniques. In this case, CPR was begun
within the 4-minute recommendation. An ambulance, equipped
and staffed to provide ACLS, arrived within 6 minutes. The
standards and guidelines for CPR within 4 minutes, and ACLS within
8 minutes, were met and the worker did survive.
In Case #2, the worker's contact with
electrical energy was prolonged and a coworker who aided him
received an electrical shock, because coworkers did not know how
to de-energize the circuit. The optimal times for CPR and
ACLS were exceeded, and the resuscitation was unsuccessful.
Providing appropriate medical care after an electrical energy
incident will not guarantee success. However, it has been
reported elsewhere and supported in the NIOSH case reports, the
chance for successful resuscitation after cardiopulmonary arrest
is best when the criteria for providing emergency care are met.
Last Update:
2006-09-21
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