The necessity of UL certification for electric fans
safety is a major concern when designing and manufacturing fans and blowers. In the US market, any product containing electronic components sold for public use must bear the Underwriters Laboratories (UL) listed mark. Federal, state, and local building codes also require that any electrical equipment sold for use in a new public building must bear the UL Listed Mark.
Building inspectors will check all electric equipment for this mark. OSHA will look for this sign during safety inspections in the workplace. Since its founding in 1894, UL has played a key role in the safety system in the United States. The UL mark has become the most familiar safety mark in the United States.
Electric fan UL certification standards
UL Standard for Safety UL 507 Fans
the UL507 standard applies to non-industrial fans and blowers. One is fans for air circulation, such as table fans and ceiling fans; the other is fans for ventilation, such as fans for attics, walls, windows and household range hoods. Fans in this category must be installed in accordance with NEC.
The test is similar to the UL 705, with additional starting current test, humidity regulation test and optional speed control test. Greenheck ceiling fans and cabinet fans meet UL 507 standards.
Electric fan UL507 standard applicable product range
1) These requirements include:
a) Fans and blowers for circulating air, such as table, ceiling and ceiling fans;
b) Ventilation fans and blowers, such as attic, wall-mounted fans, ceiling plug-in, household range hoods and canopy types, and window sashes;
c) A fan of the dryer type used to dry the carpet or floor;
d) Evaporative cooler;
e) Air filtration equipment;
f) Fan deodorant and air freshener;
g) Assembly fan;
h) Low pressure pack fan.
These products are rated at 600 volts or less and are intended for use in accordance with the National Electrical Code ANSI/NFPA 70.
2) These requirements do not include air heaters containing fans, heating-ventilation devices or blowers, which contain components of equipment such as furnaces, mechanical refrigeration equipment or air conditioners.
3) These requirements do not include the fuse that disconnects the fan or closes the blinds in the event of a fire.
4) These requirements do not include fans used in cooking areas when the fans are not used for household purposes.
5) These requirements do not include:
a) Fans for use in hazardous locations as defined in the National Electrical Code ANSI/NFPA 70;
b) Installed on solvents or chemically flammable liquids or vapors;
Electric fans shall be tested and the temperature shall not be high enough to cause fire, damage to the materials used or exceed the specified temperature rise.
When testing the electric fan, the protection device shall not operate. All temperature appreciation values are based on an environment of 86 °F. However, the test may be performed in any environment in the range of 50 ° - 104 °F.
If the thermocouple can be installed without removing the overall insulating potting compound on the motor, the thermocouple can be used to determine the temperature of the winding. If thermocouple measurements are not possible, the rheostatic method is used. The standard covers the connection, placement, size of the wires to be used, calibration of the instruments used, and procedures for running tests.
Electric fans shall operate under load. Multi-speed motors shall be tested at each speed. Reversible electric fans shall be tested in both directions. This will continue until a constant motor temperature is reached. The test voltage is also specified.
4. Undervoltage test
the electric fan should start and run continuously under the restricted air inlet as described above, which will generate the maximum load, but the voltage is reduced to 85% of the rated voltage of the motor.
5. Dielectric voltage withstand test
the electric fan should withstand the application of 60Hz charge between live parts and dead metal parts for one minute at the highest temperature reached during normal use without failure.
The test voltage shall be:
a) 1000 volts for electric fans using motors with a rated voltage of 12 hp or less and 250V or less.
B) 1,000 volts plus a service rated voltage greater than 12hp or exceeding 250 volts.
In order to determine whether the electric fan meets the requirements, a transformer of 500 volt ampere or greater is used for testing, in which the output voltage can be changed. The applied load was gradually increased from zero to the desired test voltage and held at that value for one minute. The increase in load should increase at a uniform rate and as fast as the voltmeter correctly indicates its value.
6. Water spray test
the electric fan should be installed according to the actual use, and spray water for 4 hours as described in the standard. If the ventilator draws air into the unit for motor cooling, the unit must be operated during the test. Insulation resistance and dielectric tests should be performed immediately after exposure to water spray and repeated after 12 hours.
After the test, there shall be no water at any point where the field-installed wiring and uninsulated live parts or the joints on the coated wires other than the motor windings may come into contact.
7. Metal coating thickness test
this test is used to determine the thickness of zinc and cadmium coatings to ensure that the metal surface is protected from destructive rust and corrosion.
8. Mark persistence test.
This series of tests is designed to ensure that any label used for identification or warning on UL certified products has good adhesion and can prevent fouling or removal due to scratches. These tests include oven aging, immersion, standard atmosphere, abnormal condition exposure, and outdoor exposure tests.
9. Capacitor test
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