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UL 1730-2017 pdf free download
UL 1730-2017 pdf free download.Smoke Detector Monitors and Accessories for Individual Living Units of Multifamily Residences and Hotel/Motel Rooms.
19.2 An uninsulated dead metal part of a cabinet, electrical enclosure, motor frame or mounting bracket, capacitor, or other electrical component shall be bonded for grounding If the part may be contacted by the user or by service personnel when servicing the unit.
Exception No. 1: An adhesive-attached, metal-toil marking, screw, handle, or the like, that is located on the outside of an enclosure or cabinet and isolated from electrical components or wiring by grounded metal pails so that it is not likely to become energized, need not be bonded.
Exception No. 2: An isolated metal part, such as a relay frame or armature, assembly screw, or the like, that is separated from both wiring and uninsulated live metal parts need not be bonded.
Exception No. 3: A panel or cover that does not enclose uninsulated live parts need not be bonded if wiring is separated from the panel or cover so that ills not likely to become energized.
Exception No. 4: A panel or cover need not be bonded if it is insulated from electrical components and wiring by an insulating barrier of vulcanized fiber, varnished cloth. phenolic composition, or similar material not less than 1/32 inch (0.8 mm) thick and secured in place.
19.3 A bonding means may be used as an electrical conductor. it of ferrous metal, it shall be protected against corrosion by painting, plating, or a means determined to be equivalent. A separate bonding conductor shall be installed so that it is protected from mechanical damage.
19.4 The bonding shall be by a positive means, such as by clamping, riveting, bolted or screwed connection, brazing, or welding. The bonding connection shall penetrate nonconductive coatings such as paint. Bonding around a resilient mount shall not depend on the clamping action of wbber or similar material.
19.5 A bolted or screwed connection that incorporates a star washer or serrations under the screwhead may be used for penetrating nonconductive coatings as required in 19.4.
19.6 If the bonding means depends upon screw threads, either two or more screws or two full threads of a single screw engaging metal may be used.
19.7 A metal-to-metal hinge-bearing member for a door or cover may be used as a means for bonding the door or cover for grounding, if a multiple bearing-pin type (piano-type) hinge is used.
Exception: Slip-joint or similar hinge-bearing members need not comply with this requirement if the resistance between the two parts connected by the bonding element is not more than 0.1 ohm.
19.8 The size of a copper or aluminum conductor used to bond an electrical enclosure shall be based on the rating of the branch-circuit overcurrent device by which the unit will be protected. The size of the conductor shall be as specified in Table 19.1.UL 1730-2017 pdf free download.
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