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What is the rating of the number of switching operations of Square D, 30 - 60A, Heavy Duty, F-Series Safety Switches? These ratings are also sometimes referred to as Endurance operations and Horsepower-overload operations.

Issue:
Application

Product Line:
HD Safety Switch

Cause:
Application

Resolution:
For Safety Switches, the standard for design and testing of the number of switching operations is governed by UL98 and NEMA KS-1.There are two separate tests: (1) Endurance Test, and (2) Horsepower-overload test. The below table shows the minimum number of operations required (OFF to ON to OFF) by UL and NEMA. For the endurance test, however, Square D 30 and 60A F-Series Safety Switches exceed the UL and NEMA requirements by more than 3 times the total (see below table):

NUMBER OF OPERATIONS
Square D Safety Switches (F-series)
30 - 60A, Heavy Duty
-------------------------Endurance test # of ops------------------. . . . . . . ----HP test # of ops-
test stds.....rated Load*...... No-Load...... total (L + NL) . . . . . . . . . . . . . at rated HP**
UL...................6000..................4000.................10000 . . . . . . . . . . . . . . . . . . . . 50
NEMA............8000..................7000.................15000 . . . . . . . . . . . . . . . . . . . . 50
Square D.........8000................42000.................50000 . . . . . . . . . . . . . . . . . . . . 50
* endurance test done at switch rated Load current
** horsepower test - make/break motor inrush/locked rotor current at rated HP


CTA-ID : 2000482
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