13
4-5.
Cable Disconnect Status Indicators
The SAFE and UNSAFE LED's indicate whether or not it is safe to disconnect the test leads from the load.
When a highly inductive load is being measured, a potentially lethal back-EMF is induced when the test
current is removed. The 4300B provides a discharge path for this back-EMF and monitors the voltage. The
SAFE LED is illuminated when the back-EMF is less than five volts.
CAUTION: Although the 4300B is protected against up to 500 Amps of inductive kickback, it is not
advisable to remove test leads with the Test Current On, or with the UNSAFE LED lit. In some
extreme applications if leads are removed or pull loose before the SAFE LED is lit, damage may occur
to the 4300B and/or injury to the operator!
The UNSAFE LED is also illuminated whenever a test current of .1A or greater is selected and the Test
Current is turned On, regardless of the load.
