HBM Genesis series Technical Note page 6

GN610, GN611 Isolation and type testing
Additional means of protection in case of single fault conditions
Accessible parts shall be prevented from becoming HAZARDOUS LIVE IN
SINGLE FAULT CONDITION. The primary means of protection (see
Figure 1.2) shall be supplemented by one of A, B, C or D. Alternatively one of
the single means of protection E or F shall be used. See Figure 1.2.
Figure 1.2: Acceptable arrangement of protective means against electric shock
Example: A measurement device is specified as 600 V CAT II reinforced
insulation, maximum input voltage 1000 V DC.
Using the above information one can deduct that this specification informs the
user that the measurement device is tested on input to chassis ground 5 s at
3.510 V RMS and impulse 6.400 V. The maximum operating input voltage is
1000 V DC. This device is to be used to measure CAT II circuitry up to 600 V.
6 HBM public