FL-20A Instruction Manual - Page 37
Model FL-20A Cable Fault Locator
By Walter Skuggevig, Research Department, Melville, reprinted
courtesy of Underwriters Laboratories Inc. is technical paper
was presented in December 1993 at the National Conference
on Electric Vehicle Infrastructure, sponsored by the Electric
Power Research Institute, Arizona Public Service, Salt River
Project, and the Electric Vehicle Association of the Americas.
Before electric shock can be addressed with a view
toward prevention, the term and the concept should be
explained. ere are a number of physiological eects that
can occur from electric current through the human body.
From the standpoint of electrical safety, critical physiologi-
cal eects are startle reaction - related to perception, muscle
tetanization, ventricular brillation and burns. each eect
occurs at a dierent or increased level of electric current.
A few microamperes available from a conductive surface
can be felt as a tingling sensation if the conductive surface
is lightly rubbed or tapped with the nger. ese small cur-
rents are harmless, but if perceived by a consumer, the “elec-
tric” sensations might appear sinister. e tingling sensation
can raise suspicions, although perhaps not warranted, about
the safety of a product.
A 60-Hz sinusoidal current over 0.5 mA RMS can cause
an involuntary startle reaction, particularly in women. e
current itself is harmless, but the uncontrolled movement
of a startled person can cause secondary accidents including
spills and falls. e American National Standards Institute
(ANSI) document C101-1992 species 0.5 mA as the gen-
eral limit for 60-Hz leakage current from appliances.
At frequencies lower and higher than power distribu-
tion frequencies, higher current is necessary to produce the
same level of sensation. For direct current, a limit of 2 mA
is often used. Continuously owing direct current may not
produce a particularly strong sensation, but a sudden change
in the current caused either by making or breaking the cir-
cuit can produce a strong, momentary sensation. e higher
the DC current, the stronger the sensation when the current
is started or interrupted. At frequencies of approximately 1
Electric Shock Considerations for
Electric Vehicle Charging Systems
Electric Shock - What Is It?
Perception and
Startle Reaction
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