Service manual

STP 11-25R13-SM-TG
T - 4
T-12. Summary of Lethal Effects of Electric Current.
a. If long continued, currents in excess of one's let-go-current may produce collapse,
unconsciousness, and death.
b. Currents flowing through the chest, the head, or nerve centers controlling respiration may
produce respiratory inhibition. Respiratory inhibition is dangerous because paralysis of the respiratory
organs may last for a considerable period even after interruption of current, and the approved method of
artificial resuscitation must be applied promptly to prevent suffocation.
c. Moderately small currents that produce over-stimulation of the heart rather than physical
damage to that vital organ cause ventricular fibrillation. When fibrillation occurs, the rhythmic pumping
action of the heart ceases and death usually follows in a few minutes.
d. Relatively high currents may cause heart standstill.
e. Relatively high currents may produce fatal damage to the central nervous system.
f. Relatively high currents may produce deep burns, and currents sufficient to materially raise
body temperature produce immediate death.
g. Victims who have been revived sometimes die suddenly without apparent cause. This is
thought to be due to aggravation of preexisting conditions, the result of hemorrhages affecting vital
centers, or the effects of shock to the nervous system. Delayed death may be also due to burns or other
complications.
h. Additional information for a better understanding of current flow is provided in TB MED 286.
T-13. First Aid for Severe Shock Victims.
It has been observed that not all maintenance personnel are clearly familiar with first aid procedures
for victims of severe shock. Many victims of electrocution could have been saved if associates had
realized the value of administering first aid procedures even after cessation of heartbeat. The importance
of continuing cardiopulmonary resuscitation (CPR) in apparently dead victims cannot be overemphasized.
Cases have been reported where complete recovery of such victims has been achieved even after many
minutes of stopped or fibrillation heart action and cessation of respiratory function.
T-14. Placarding.
AR 385-30 (Safety Color Code Markings and Signs) provides the required guidance for color coding
of facilities and placarding areas with conspicuous warning signs, where voltage is a hazard. Electrical
and electronic circuits will be marked in accordance with MIL-STD-454.
T-15. General Safety Precautions.
NOTE: The following precautions are provided to identify minimal safety
requirements:
a. Equipment producing a tingle will be reported promptly for repair. Insulation leakage becomes
progressively worse and can become extremely hazardous, especially where contact may readily be
made against the metal framework of an exhaust hood, pipes, damp floor, or bench surfaces. Do not rely
on grounding to mask a defective circuit. Do not attempt to correct a fault by using a larger fuse.
b. When equipment is deenergized, high-voltage capacitors must be discharged before working
on or near them. Use a shorting bar to discharge capacitors and leave in place while maintenance work
is being performed. If capacitors become recharged during repair or preventive maintenance operations,