UL 1711:2006 pdf download – Amplifiers for Fire Protective Signaling Systems
UL 1711:2006 pdf download – Amplifiers for Fire Protective Signaling Systems.
39 Leakage Current Test
39,1 It the open circuit potential is greater than 42.4 volts peak as measured between any accessible part and:
a) Earth ground or
b) Any other accessle part,
the leakage current at any accessible part shall not be more than the following values tested in accordance with 39.2 — 39.8:
1) 0.5 milliampere for an ungrounded (2.wire) portable. stationary, or fixed product:
2) 0.5 milhampere for a grounded (3-wire) portable Product; and
3) 0.75 millianipere for a grounded (3-wire) stationary or fixed product.
Exception: If an electromagnetic radiation suppression filter is necessary for the product to function as intended, the ‘eakage current may be not more than 2.5 milliamperes if the product con’phes with the following conditions:
a) The product is provided with grounding means in accordance with the applicable requirements for a cord connected product in Bonding for Grounding, Section 20;
b) With the filter removed from the product, the leakage current does not exceed the limits specified in (1) and (2), as applicable: and
c) The product ie marked in accordance with 56. t3.
39.2 With reference to the requirements of 39.1, leakage current refers to all currents, including capacitively coupled currents, that may be conveyed between exposed conductive surfaces of the equipment and ground, or between exposed conductive surfaces of the equipment.
39.3 Leakage currents from all exposed surfaces are to be measured to the grounded supply conductor individually as well as collectively where exposed surfaces are simultaneously accessible, and from one surface to another where &multaneously accessible (see 38.6). A part is considered to be an exposed surface unless it is guarded by an enclosure considered to protect against the risk of electric shock.
39.4 With reference to 39.3, if all accessible surfaces are bonded together and connected to the grounding conductor of the power-supply cord, the leakage current may be measured between the grounding conductor and the grounded supply conductor. If exposed dead metal parts of a product are connected to the neutral supply conductor, this connection is to be open during the measurement.
39.5 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 4 by 8 inches (10 by 20 cm) in contact with the surface. If the surface is less than 4 by 8 inches, 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 product.
39.7 Unless the meter is being used to measure current from one part of a product to another, the meter is to be connected between the accessible parts and the grounded supply conductor.
39.8 A sample of the product is to be tested initially in the as’recerved condition with all switches closed. but with its equipment-grounding conductor, If any, open at the attachment plug. A Product that has not been energized for a minimum of 48 hours prior to the test, and that is at room temperature, is considered to be in the as•received condition. The supply voltage is to be the maximum voltage marked on the product, but not less than 120 or 240 volts. The test sequence, with reterence to the measuring circuit In Figure 39.1, is to be as follows:
a) With switch Si open, the product is to be connected to the measuring c*rcuit. Leakage current is to be measured using both positions of switch S2, and with the product switching devices in all of their normal operating positions.
b) Switch Si is then to be closed, energizing the product, and within 5 seconds the leakage current is to be measured using both positions of switch S2, and with the product switching devices In all their normal operating positions.
C) Leakage current is to be monitored until thermal stabilization. Both positions of switch S2 are to be used in determining this measurement. Thermal stabilization is to be obtained by
operation of the product as in the Temperature Test. Section 40.