Manual
19 
714-921-9095 
TEST INSTRUMENT SAFETY 
(continued from inside front cover) 
6. 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 custom er. When 
the cabinet is removed for servicing, a serious shock hazard exists if the chassis is touched. Not on ly 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 t est 
instruments to a “hot chassis”. To test “hot chassis” equipment, always connect an isolation transformer between the ac outlet and the 
equipment under test. The B+K Precision Model TR-110 or 1604 Isolation Transformer, or Model 1653 or 1655 AC Power Supply is 
suitable for most applications. To be on the safe side, treat all two-wire ac equipment as “hot-chassis” unless you are sure it has an 
isolated chassis or an earth ground chassis. 
7. On test instruments or any equipment with a 3-wire ac power plug, use only a 3-wire outlet. This is a safety feature to keep the housing 
or other exposed elements at earth ground. 
8. B+K Precision products are not authorized for use in any application involving direct contact between our product and the human 
body, or for use as a critical component in a life support device or system. Here, “direct contact” 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. 
9. Never work alone. Someone should be nearby to render aid if necessary. Training in CPR (cardio -pulmonary resuscitation) first aid 
is highly recommended. 










