BK Precision 5105B, Instruction Manual, Page: 2 / 48

TEST INSTRUMENT SAFETY
WARNING
Normal use of test equipment exposes you to a certain amount of danger from electrical shock because testing
must sometimes be performed where exposed high voltage is present. An electrical shock causing 10 milliamps of
current to pass through the heart will stop most human heartbeats.Voltage as low as 35 volts dc or ac rms should
be considered dangerous and hazardous since it can produce a lethal current under certain conditions. Higher volt-
ages are even more dangerous.Your normal work habits should include all accepted practices to prevent contact
with exposed high voltage, and to steer current away from your heart in case of accidental contact with a high volt-
age. Observe the following safety precautions:
1.There is little danger of electrical shock from the dc output of this power supply. However, there are several
other possible test conditions using this power supply that can create a high voltage shock hazard:
a. If the equipment under test is the "hot chassis" type, a serious shock hazard exists unless the equipment is
unplugged (just turning off the equipment does not remove the hazard), or an isolation transformer is used.
b. If the equipment under test is "powered up" (and that equipment uses high voltage in any of its circuits), the
power supply outputs may be floated to the potential at the point of connection. Remember that high voltage may
appear at unexpected points in defective equipment. Do not float the power supply output to more than 100 volts
peak with respect to chassis or earth ground.
c. If the equipment under test is "off" (and that equipment uses high voltage in any of its circuits under normal
operation), discharge high-voltage capacitors before making connections or tests. Some circuits retain high voltage
long after the equipment is turned off.
2. Use only a polarized 3-wire ac outlet.This assures that the power supply chassis, case, and ground terminal are
connected to a good earth ground and reduces danger from electrical shock.
3. Don’t expose high voltage needlessly. Remove housings and covers only when necessary.Turn off equipment
while making test connections in high-voltage circuits. Discharge high-voltage capacitors after removing power.
4. If possible, familiarize yourself with the equipment being tested and the location of its high voltage points.
However, remember that high voltage may appear at unexpected points in defective equipment.
5. Use an insulated floor material or a large, insulated floor mat to stand on, and an insulated work surface on
which to place equipment; and make certain such surfaces are not damp or wet.
6.When testing ac powered equipment, the ac line voltage is usually present on some power input circuits such as
the on-off switch, fuses, power transformer, etc. "any time" the equipment is connected to an ac outlet.
7. B+K Precision products are not authorized for use in any application involving direct contact between our prod-
uct and the human body, or for use as a critical component in a life support device or system. Here, "direct con-
tact" refers to any connection from or to our equipment via any cabling or switching means. A "critical component"
is any component of a life support device or system whose failure to perform can be reasonably expected to cause
failure of that device or system, or to affect its safety or effectiveness.
8. Never work alone. Someone should be nearby to render aid if necessary.Training in CPR (cardio-pulmonary
resuscitation) first aid is highly recommended.