What does the Trip Class 10, Class 20 and Class 30 mean for overload relays?

Issue:
Meaning of Trip Classes for overload relays.

Product Line:
NEMA Overload Relays

Environment:
North American Products

Resolution:
The trip class means that at 600% (6 times) of the maximum thermal current rating (or 600% of the actual dial setting on adjustable overloads) the Class 10 will trip in 10 seconds or less, Class 20 will trip in 20 seconds or less, and Class 30 will trip in 30 seconds or less.

Released for:Schneider Electric Ireland