Elenco 30MHz Dual Trace - Manual (Page 5)

7. Some equipment with a two-wire ac power cord, including some with polarized
power plugs, is the "hot chassis" type. This includes most recent television receivers
and audio equipment. A plastic or wooden cabinet insulates the chassis to protect
the customer. When the cabinet is removed for servicing, a serious shock hazard
exists if the chassis is touched. Not only does this present a dangerous shock
hazard, but damage to test instruments or the equipment under test may result
from connecting the ground lead of most test instruments (including this
oscilloscope) to a "hot chassis". To make measurements in "hot chassis"
equipment, always connect an isolation transformer between the ac outlet and the
equipment under test. To be on the safe side, treat all two wire ac powered
equipment as "hot chassis" unless you are sure it has an isolated chassis or an earth
ground chassis.
8. Never work alone. Someone should be nearby to render aid if necessary. Training in
CPR (cardio-pulmonary resuscitation) first aid is highly recommended.
9. Equipment limited for use in CS AND RS controlled environmental conditions.
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TEST INSTRUMENT SAFETY