3-16
Asbestos is a general term used to describe several fibrous mineral silicates. Major uses of asbestos
include asbestos cement products, floor tiles, fireproofing, high-temperature insulation, asbestos cloth,
friction materials (such as brake linings and clutch facings), various gasket materials, and miscellaneous
other products.
Inhaling asbestos fibers can produce disabling or fatal fibrosis of the lungs. Fibrosis of the lungs
(asbestos) comes from inhaling asbestos fibers. Asbestos is a factor in the development of lung cancer as
well as cancer of the gastrointestinal tract. It may take 20 to 40 years between initial exposure to asbestos
and the appearance of a cancerous condition. Know where asbestos is in your environment and avoid or
take precautions to prevent exposure.
ELECTRICAL OR ELECTRONIC CIRCUITS AND PORTABLE POWER TOOLS
When working on electrical or electronic circuits, you must observe certain general precautions. The
following is a listing of common sense safety precautions that you must observe at all times:
Remember that electrical and electronic circuits often have more than one source of power. Take
time to study the schematics or wiring diagrams of the entire system to ensure that all power
sources are deactivated.
Remove all metal objects from your person.
Use one hand when turning switches on or off. Keep the doors to switch and fuse boxes closed,
except when working inside or replacing fuses.
After first making certain that the circuit is dead, use a fuse puller (figure 3-13) to remove
cartridge fuses.
Figure 3-13.—Fuse puller.
!All supply switches or cutout switches from which power could possibly be fed should be secured
in the OFF or OPEN (safety) position and tagged (figure 3-14). The tagging procedures must be done in
accordance with the appropriate manual or instruction for your field of training.
