Keithley 2002 Getting Started Manual page 6

If a screw is present, connect it to safety earth ground using #18 AWG or larger wire.
The symbol on an instrument or accessory indicates that 1000V or more may be present
on the terminals. Refer to the product manual for detailed operating information.
Instrumentation and accessories should not be connected to humans.
Maintenance should be performed by qualified service personnel. Before performing any
maintenance, disconnect the line cord and all test cables.