UL 982-2021 pdf download – Motor-Operated Household Food Preparing Machines.
31.4 An appliance rated 50 – 60 Hz is to be tested both at 50 and 60 Hz, where performance is frequency dependent, unless it can be established that one test will result in the maximum operating conditions. Universal motors are generally considered not frequency dependent. 31.5 Wherever cloth is mentioned in the abnormal tests, the cloth is to be bleached cheesecloth, running 14 – 15 yd 2 /lb (approximately 26 – 28 m 2 /kg) and having what is known in the trade as a “count of 32 by 28,” that is, for any square inch, 32 threads in one direction and 28 threads in the other direction (for any square centimeter, 13 threads in one direction and 11 in the other direction). 31.6 Unless otherwise specified, an appliance intended to be supplied by a Universal Serial Bus (USB) shall be tested with the appliance connected to a continuous independent DC source of supply with a voltage of 1.05 times the rated voltage and a current capacity of 8 A. 31.7 An appliance intended to be supplied by an automotive adapter shall be tested with the appliance connected to a continuous independent source of supply of 12 V dc. 32 Leakage Current Test 32.1 The leakage current of a cord-connected appliance rated for a nominal 120 V supply when tested in accordance with 32.3 – 32.7 shall not be more than: a) 0.5 mA for an ungrounded (two-wire) portable, stationary, or fixed appliance; b) 0.5 mA for a grounded (three-wire) portable appliance; and c) 0.75 mA for a grounded (three-wire) 3-wire or 4-wire stationary or fixed appliance employing a standard attachment plug rated 20 A or less.
32.3 All accessible conductive surfaces are to be tested for leakage currents. The leakage currents from these surfaces are to be measured to the grounded supply conductor individually as well as collectively where simultaneously accessible and from one surface to another where simultaneously accessible. Parts are considered to be accessible surfaces unless guarded by an enclosure considered to provide protection against the risk of electric shock as defined in 7.6 – 7.12. Surfaces are considered to be simultaneously accessible when they can be readily contacted by one or both hands of a person at the same time. These measurements do not apply to terminals operating at voltages which are not considered to involve the risk of electric shock. 32.4 If a conductive surface other than metal is used for the enclosure or part of the enclosure, the leakage current is to be measured using a metal foil with an area of 10 by 20 cm (3.9 by 7.9 inches) in contact with the surface. Where the surface is less than 10 by 20 cm, the metal foil is to be the same size as the surface. The metal foil is not to remain in place long enough to affect the temperature of the appliance. 32.5 The measurement circuit for leakage current is to be as shown in Figure 32.1. The ideal instrument is defined in (a) – (d). The meter which is actually used for a measurement need only indicate the same numerical value for a particular measurement as would the defined instrument. The meter used need not have all the attributes of the defined instrument. a) The meter is to have an input impedance of 1500 ohms resistive shunted by a capacitance of 0.15 μf. b) The meter is to indicate 1.11 times the average of the full-wave rectified composite waveform of voltage across the resistor or current through the resistor.