Das Datenblatt sagt auf Seite 2:
"The NKE series has been recognized by Underwriters Laboratory for
functional insulation. Both input and output should normally be
maintained within SELV limits i.e. less than
42.4V peak, or 60VDC. The isolation test voltage represents a measure of
immunity to transient voltages and the part should never be used as an
element of a safety isolation system.
The part could be expected to function correctly with several hundred
volts offset applied continuously across the isolation barrier; but then
the circuitry on both sides of the
barrier must be regarded as operating at an unsafe voltage and further
isolation/insulation systems must form a barrier between these circuits
and any user-accessible circuitry
according to safety standard requirements."
Das ist doch eindeutig.
Bernhard