Shock Current in
milli-Amperes
(RMS mA)
Circuit
Resistance at
120 Volts AC
Physiological Effects
0.5 to 7mA
240,000 down to
17,000 ohms
Threshold of Perception: Large enough to excite skin
nerve endings for a tingling sensation. Average thresholds
are 1.1 mA for men and 0.7 mA for women.
1 to 6 mA
120,000 down to
20,000 ohms
Reaction Current: Sometimes called the Surprise
current. Usually an involuntary reaction causing the
person to pull away from the contact.
6 to 22 mA
20,000 down to
5,400 ohms
Let-Go Current: This is the threshold where the person can
voluntarily withdraw from the shock current source. Nerves
and muscles are vigorously stimulated, eventually resulting
in pain and fatigue. Average let-go thresholds are 16 mA for
men and 10.5 mA for women. Seek medical attention.
15 mA and above
8,000 ohms and
below
Muscular Inhibition: Respiratory paralysis, pain and fatigue
through strong involuntary contractions of muscles and
stimulation of nerves. Asphyxiation may occur if current is
not interrupted.
60 mA to 5 A
2,000 down to 24
ohms
Ventricular Fibrillation: Shock current large enough to
desynchronize the normal electrical activity in the heart
muscle. Effective pumping action ceases, even after shock
cessation. Defibrillation (single pulse shock) is needed or
death occurs.
1 A and above
120 ohms and
below
Myocardial Contraction: The entire heart muscle
contracts. Burns and tissue damage via heating may
occur with prolonged exposure. Muscle detachment from
bones possible. Heart may automatically restart after
shock cessation.