Getting Started Tutorial 1
Keysight U3402A User’s and Service Guide 31
The terminals at a glance
Figure 1-8 Input terminal
To avoid damaging this multimeter, do not exceed the rated input limit.
Voltages above 300 VAC may be measured only in circuits that are isolated from 
mains. However, transient overvoltages are also present on circuits that are 
isolated from mains. The Keysight U3402A is designed to safely withstand 
occasional transient overvoltages up to 2500 V PEAK. Do not use this multimeter 
to measure circuits where transient overvoltages could exceed this level.