9.
SAFETY IS EVERYONE'S BUSINESS.
TB 385-4 Safety Precautions for Maintenance of Electrical/Electronic
Equipment covers this subject in detail and Army Correspondence Course OD
0836 Organizational Maintenance covers shop practices. Shown below are some
special safety considerations for calibration. Although safety is a command
responsibility, the application of safety principles rests with the
supervisor and, ultimately, with the individual.
a. Reporting.
Accidents causing injury to personnel or
equipment
damage shall be reported to the local Safety Office.
b. Electrical/Electronic Equipment. The term HIGH VOLTAGE is used in
many instructions without specifying where low voltage ends and high voltage
begins. It is important to note that voltage is only the electromotivating
force pushing the current. It is the current that kills, not the voltage.
For our purposes 500 volts rms (root-mean-square) or 500 volts direct
current (do) and above is defined as HIGH VOLTAGE. Do not be misled by the
term LOW VOLTAGE. Under adverse conditions, much lower potentials may cause
death.
(1) Physiological Effects of Electrical Current.
A detailed
discussion of the physiological effects of electric shock is beyond our
scope; however, it is important to outline the key factors which play a role
in determining the relative hazards of shock through the human body.
In
various studies, it has been determined that several factors are important
in determining severity of injury from electrical shock.
(a) The current path through the body.
(b) The frequency, if alternating current.
(c) Susceptibility of heart in the different phases of the cardiac
cycle.
(d) Duration of the shock of discharge.
(e) Repeated shocks in different phases of the heart action.
(f) Current magnitude.
(g) Skin resistance and whether voltage is sufficient to break
down skin resistance.
(2) Levels of Effect.
It is well known that current, not voltage,
determines the physiological effect.
It is useful to distinguish
quantitatively between at least four levels of effects due to continuous
current:
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