UL 294:2005 pdf download – UL Standard for Safety for Access Control System Units
UL 294:2005 pdf download – UL Standard for Safety for Access Control System Units.
43 DIelectric Voltage-Withstand Test
43,1 An access control system unit shall withstand for 1 minute, without breakdown, the application of an essentially sinusoidal AC potential of a frequency within the range of 40 — 70 hertz, or a DC potential, between live parts and the enclosure, l,ve parts and exposed dead-metal parts, and live parts of circuits operating at different potentials or frequencies. The test potential is to be (also, see 43.2):
a) For an access control system unit rated 30 volts AC rms (42.4 volts DC or AC peak) or less — 500 volts (707 volts, if a DC potential is used).
b) For an access control system unit rated between 31 and 250 volts AC rms — 1000 volts (1414 volts, if a DC potential is used),
C) For an access control system unit rated more than 250 volts AC mis — 1000 volts plus twice the rated voltage (1414 volts plus 2,828 times the rated AC mis voltage, Eta DC potential is used).
43.2 For the application of a potential between live parts of circuits operating at different potentials or frequencies, the voltage is to be the applicable value specified in 43,1 (a). (b), or (C). based on the highest voltage of the circuits under test instead of the rated voltage of the access control system unit. Electrical connections between the circuits are to be disconnected before the test potential is applied.
43.3 Exposed dead-metal parts referred to in 43.1 are noncurrent-carrying metal parts that are likely to become energized and are accessible from outside of the enclosure of a unit during intended operation with the door of the enclosure closed.
43.4 If an autotransformer is in the circuit, the primary of the transformer is to be disconnected and an AC test potential in accordance with 43.1(c) is to be applied directly to all wiring involving more than 254) volts.
43.5 It the charging current through a capacitor or capacitor type filter connected across the line, or from line to earth ground, is sufficient to prevent maintenance of the specified AC test potential, the capacitor or filter is to be tested using a DC test potential in accordance with 43.1.
43.6 The test potential may be obtained from any convenient source having sufficient capacity to maintain the specified voltage. The output voltage of the test apparatus is to be monitored. Starting at zero, the potential is to be increased at a rate of approximately 200 volts per minute until the required test value Is reached and is to be held at that value for 1 minute.
43.7 A printed wiring assembly or other electronic circuit component that would be damaged by the application of. or would short-circuit, the test potential, is to be removed, disconnected, or otherwise rendered inoperative before the test. A representative subassembly may be tested instead of an entire access control system unil Rectifier diodes in the power supply may be Individually shunted before the test to avoid destroying them in the case of a malfunction elsewhere in the secondary circuits.
44 Temperature Test
44.1 The materials used in the construction of an access control system unit shall not attain temperature rises greater than those indicated in Table 44.1.
44.6 To determine compliance with these requirements, the product is to be connected to a supply circuit of rated voltage and frequency in accodance with 28.3.1 and operated continuously under representative service conditions that are expected to produce the highest temperature.
44.7 If a current-regulating resistor or reactor is provided as a part of a unit. it is to be adjusted for the maximum resistance or reactance at normal cwrent.
44.8 The test is to be continued until:
a) Constant temperatures are attained during the normal standby condition and
b) The product has functioned ba’ 1 hour at a rate of 3 intended access operations per minute. 45 Abnormal Operation Test
45.1 The introduction of abnormal fauft conditions shall not increase the risk of fire or electric shock while the access control system unit is operating.
452 To determine compliance with the requirement in 451. the product is to be connected to a source of supply in accordance with 28.3.1 and operated under the most severe anticipated circuit-fault conditions. There shall not be emission of flame or molten metal, or any other manifestation of a fire (see 45.4) or dielectric breakdown when the product Is tested in accordance with the Dielectric Voltage-Withstand Test, Section 43.