Page 2 - FL-20A Instruction Manual
Model FL-20A Cable Fault Locator
High Voltage Facts
The commonly accepted maximum values of 60 Hz. current passing
through the human adult body which permit a subject to let go of elec-
trodes are nine milliamperes for males and six milliamperes for females.
At 3000 Hz. this value increases to about 22 milliamperes for men or 15
milliamperes for women. DC currents do not present the same let–go
problems, but a subject can readily let go at a level of 60 milliamperes.
A continuous 60 Hz. current above 18 milliamperes stops breathing for
the duration of the shock only. Ventricular fibrillation may occur above
a level of 67 milliamperes. The reaction current level of 60 Hz. is about
.5 milliamperes. Above this level a muscular reaction can occur which
can cause a secondary accident. The DC and 3 kHz. levels are probably
considerably higher.
Capacitor discharge energy of 50 Joules (watt–seconds) is regarded as
hazardous.
For references, see: Dalziel, Ogden, Abbot, “Effect of Frequency on
Let–Go Currents,” Transactions of A.I.E.E., Volume 62, December
1943, and Dalziel, “Electric Shock Hazard,” I.E.E.E., Spectrum, Febru-
ary 1972.
Safety Symbols
The symbols depicted below are safety symbols placed on the spark test
equipment. It is important to understand the meaning of each.
The Caution symbol found in the instruction manual calls attention to
a procedure, practice, or the like, which if not correctly performed or
adhered to, could result in personal injury or damage to or destruction
of part or all of the product. Do not proceed beyond a Caution symbol
until the indicated conditions are fully understood and met.
Risk of electric shock symbol.
Earth (ground) symbol.
Environmental Conditions
The Model FL-20A Cable Fault Locator is designed to be safe under the
following conditions:
• Indoor use.
• Altitude to 2000 m.
• Temperatures from 5ºC to 40ºC.
• Humidity to 80% R.H. at 31ºC, decreasing linearly to 50% R.H. at
