IEEE C37.40-2003 pdf download IEEE Standard Service Conditions and Definitions for High-Voltage Fuses, Distribution Enclosed Single-Pole Air Switches, Fuse Disconnecting Switches, and Accessories
3.Service conditions
The capabilities, as defined in this standard, for fuses and other devices is predicated on the device beingused and applied in accordance with the manufacturer’s recommendations and under circuit conditions thatare equal to or less severe than the conditions required by the specifications and testing standards for thedevice. The environment where the fuse is used may affect its performance and shall be carefully consideredor all applications. Devices covered by this standard should not be closed into an energized circuit sincethey do not have making-current ability, and devices that do not have load-breaking means should not beopened with the circuit energized.
3.1 Usual service conditions
3.1.1 For fuses and swiches rated for use at a maximum application temperature of 40 °C
Equipment conforming to this standard that is rated for use in a maximum application temperature of 40 °Cor less shall be suitable for operation at its assigned ratings. provided the ambient temperature of thesurrounding medium is not above 40 °C or below -30 C, the altitude does not exceed 1000 m, and thefrequency of the power system is 60 Hz.
3.1.2 For fuses and switches rated for use at a maximum application temperature above40C
Equipment conforming to this standard that is rated for use in a maximum application temperature of greaterthan 40 °C shall be suitable for operation at its assigned ratings, provided the ambient temperature of the sur-rounding medium is not above its assigned maximum application temperature and it is not below -30 °C, thealtitude does not exceed 1000 m, and the frequency of the power system is 60 Hz.
3.2 Other service conditions
The majority of fuses presently manufactured conform to the service conditions listed in 3.1. Fuses can bedesigned for other service conditions and still conform to this standard and the specification standards andapplications guidelines listed in Clause 2, providing they are designed and tested with those other conditionsconsidered in the design and testing process. Fuses are routinely designed for higher altitudes and powerTrequencies that are different from 60 Hz. Applications with conditions other than those listed in 3.1 shouldbe brought to the attention of those responsible for the design and application. The following is a listing ofsome of the conditions that fuses have in the past been designed to accommmodate:
a) Altitudes in excess of 1000 m (see 3.3)
b) Power system frequencies other than 60 Hz
c) Ambient temperatures less than –30 °C
d) Exposure to damaging fumes or vapors, excessive or abrasive dust, explosive mixtures of dust or gases, steam, salt spray, excessive moisture, or dripping water
e) Exposure to abnormal vibration, shocks, or tilting
f) Exposure to abnormal transportation or storage conditions
g) Abnormal space limitations
h) Abnormal operating duty, frequency of operation, difficulty of maintenance, etc.
3.3 Correction of altitudes in excess of 1000 m
IEEE C37.40-2003 pdf download
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