Safety Guidelines For High-Voltage Testing - HP 9030 Service Manual

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Safety Guidelines for High-Voltage Testing
Here is a list of safety gUidelines to be followed when working with voltages in excess of SOV dc or
SOV ac root-mean-square (RMS).
1. Know each step of the test procedure. Check the test setup to be sure the instruments are
connected properly and that all control settings are correct.
2. Never defeat interlocks.
3. Never have one hand on chassis or other ground while measuring high voltages with a probe
held in the other hand. Use the one-hand method, that is, probe in one hand, the other hand
behind the back or in a pocket.
4. Make sure the probe being used has voltage insulation higher than the voltage being mea-
sured. Check wires and probes for cracked insulation and defects. If any defects are noted do
not use until repairs are made.
S. Make certain that the instrument to be serviced is turned off and all capacitors and high-
voltage circuits are discharged before any component or hardware is removed or touched.
Remember that a circuit can be lethally charged if a component is open or missing, or if a
wire is disconnected or open, even with the ac power switch off. Isolated heat sinks can also
be statically charged.
6. Make certain that instruments used for testing are used within their rated specification. Never
use instruments floated above their specified rating.
7. Never reach around energized high-voltage circuits. Always turn equipment off and dis-
charge the high voltage first.
8. NEVER WORK ALONE. Be familiar with location of power switches in your area and what
they control. Turn off power to free a fellow worker from high voltage without energizing
yourself.
9. Keep work area neat, free of any interfacing conductive material, and free of any sharp
objects. Remember, a reaction to a shock can cause one to strike nearby objects which can
result in a serious injury.
10. Always leave safety shields in place unless work must be done on circuits behind the shields.
11. Never leave work area with high-voltage equipment energized and high-voltage circuits
exposed.
12. Have available and use approved warning signs and tags where high-voltage testing is in
process.
13. Do not make measurements in a circuit where a corona is present. Corona can be identified
by a pale-blue color, from a buzzing sound emanating from sharp metal points in the circuit,
or from the odor of ozone.
14. Hands, shoes, floor, and workbench must be dry. Avoid making measurements under
humid, damp, or other environmental conditions that could affect the dielectric-withstanding
voltage of the test leads or instruments.
IS. All test procedures and safety procedures should be strictly followed at all times.