UL 1054:2002 pdf download – Special-Use Switches.
16 Endurance Test
16.1 A switch rated in amperes o horsepower shall be subjected to the tests described in 16.2 — 16.4. There shall be no electrical or mechanical malfunction of the switch and the fuse that Is connected to dead metal parts — see 12.9 — shall not open. At the condusion of the test, the switch shall be capable of performing its normal function and there shall be no loosening of parts or any other defect that will diminish appreciably the usefulness and reliability of the switch.
16.2 A switch is to be operated by means of its actuating member either manually or by an acceptable machine for 6000 cycles of making and breaking its rated current at a rate of 6 — 10 cycles per minute.
16.3 If an additional rating in ho4’sepower is desired for an ampere-rated alternating-current switch. (such as a heater switch) that has been tested for overload and endurance at unity power factor, an additional endurance test with an inductive load may be waived it the current rating of the switch is not less than twice the full-load motor current corresponding to the horse-power rating, However, the switch is to be subjected to the horsepower overload test in accordance with Table 15.1.
16.4 For a switch rated in horsepower only, the endurance test-current is to be the applicable value of full-load current specified ii Table 15.2 or Table 16.1.
16.5 A switch intended for the control of a tungsten-filament lamp is to be operated for an additional 6000 cycles, following the endurance test making and breaking a circuit with a load of tungsten•filament lamps or a load having equivalent current characteristics and adjusted so that the normal current flow is the rated current of the switch.
16.6 The open-circuit potential of the test circuit described in 16.5 is to be 120 ±5 volts, and the closed-circuit potential at the load with normal current flowing is to be within 5 percent of the open-circuit potential. A direct-current supply is to be used with a T-rated switch — see 233. An alternating-current supply is to be used with an L-rated switch — see 23.4.
19.2 As an alternative to the test described in 19.1, a switch that does not have the minimum spacings required by 11.1 shall withstand without breakdown for 1 minute the application of a 50 — 60-hertz essentially sinusoedal potential of twice the rated voltage plus 1000 volts, with the switch mounted as described in 194. The test potential shall be applied between live parts of opposite polarity, and between live parts and dead metal parts.
19.3 The test specified in 19.2 is to be conducted immediately following conditioning of the switch for 48
hours in a moist-air chamber at a temperature of 32 ±1C (90 ±2°F) and a relative humidity of 95 — 100
19.4 A switch that is to be tested as descnbed in 19.2 is to be mounted in its intended manner on flat sheet metal not less than 1/16 inch (1.6 mm) thick, so that the most severe normal conditions of spacing exist. However, screws or other mounting means are to be the smallest that are commercially obtainable and that are adequate for securing the switch in place as in actual service.
19.5 The test specified in 19.1 or 19.2 is to be conducted using a testing transformer, the output voltage of which is essentially sinusoidal and can be varied. Starting at zero, the applied potential is to be increased gradually until the required test level is reached, and is to be held at that level for 1 minute. The increase in the applied potential is to be at a substantially uniform rate as rapid as is consistent with its value being correctly indicated by a voltmeter.
19.6 Other than as noted in 19.7, the transformer for dielectric voltage-withstand testing is to have a capacity of not less than 500 volt-amperes and an output or secondary potential of not less than the applicable value specified in 19.1 and 19.2.
19.7 The capacity of a transformer used for the test may be less than 500 volt-amperes if there is a meter of not more than 2 percent error connected across the secondary terminals to directly measure the applied potential.
20 Limited Short-Circuit Test.