National Instruments NI 9217 Getting Started Manual page 5

Channel-to-earth ground
Continuous
up to 2,000 m
up to 5,000 m
Withstand
up to 2,000 m
up to 5,000 m
Measurement Category II is for measurements performed on
circuits directly connected to the electrical distribution system.
This category refers to local-level electrical distribution, such as
that provided by a standard wall outlet, for example, 115 V for
U.S. or 230 V for Europe.
Note
equivalent. These test and measurement circuits are not
intended for direct connection to the MAINS building
4 | ni.com | NI 9217 Getting Started Guide
Measurement Categories CAT I and CAT O are
250 Vrms, Measurement
Category II
60 VDC, Measurement
Category I
2,300 Vrms, verified by a 5 s
dielectric withstand test
1,000 Vrms, verified by a 5 s
dielectric withstand test