UL 104:2016 pdf free download – STANDARD FOR SAFETY Elevator Door Locking Devices and Contacts.
4.2.3 The mechanical lock shall hold the door in the locked position by means of gravity, a restrained compression spring, or both.
4.3 Hoistway-door, car-door and gate electric contacts
4.3.1 Hoistway-door, car-door and gate electric contacts shall be positively opened by a lever or other device attached to and operated by the car door or gate.
4.3.2 Hoistway-door, car-door and gate electric contacts shall be maintained in the open position by the action of gravity, or a restrained compression spring, both, or by positive mechanical means.
CONSTRUCTION
5 Assembly
5.1 A hoistway-door, car-door, or gate-locking device or contact shall have the strength and rigidity necessary to resist the abuses to which it may be subjected without resulting in a risk of fire, electric shock, or injury to persons due to total or partial collapse with resulting interference with the functioning of parts, loosening or displacement of parts, or reduction of spacings.
6 Enclosure
6.1 The enclosure shall be constructed and assembled so that it will withstand handling during shipment and installation.
6.2 The enclosure and parts, such as covers, shall be provided with means for firmly securing them in place.
6.3 Bolts, screws, or other parts used for mounting the device shall be independent of those used for securing parts of the device to the frame, base, or enclosure.
6.4 A sheet metal enclosure shall not be less than 0.053 inch (1 .35 mm) thick.
6.5 A cast metal enclosure, whether iron or other metal, shall be at least 1/8 inch (3.2 mm) thick at all points and of greater thickness at reinforcing ribs and door edges, and not less than 1/4 inch (6.4 mm) thick at tapped holes for conduit.
6.6 The mechanical strength of a nonmetallic enclosure shall be at least equivalent to a sheet metal enclosure of the minimum thickness specified in 6.4.
6.7 Among the factors taken into consideration when evaluating the acceptability of a nonmetallic enclosure are:
a) The mechanical strength;
b) Resistance to impact;
c) Moisture-absorption properties;
d) Combustibility and resistance to ignition from electrical sources;
e) Dielectric strength, insulation resistance, and resistance to arc tracking; and
f) Resistance to distortion and creeping at temperatures to which the material may be subjected under conditions of normal or abnormal usage.
All these factors are considered with respect to aging.
6.8 The enclosure and parts shall be arranged so that wiring connected to the device terminals would not be abraded by nor interfere with the operating parts of the device.
6.9 The enclosure shall be provided with suitable means for the connection of metal-clad cable or conduit.
6.10 Live screwheads or nuts on the underside of a base shall be reliably prevented from loosening and shall be adequately insulated or spaced from the mounting surface. This may be accomplished by:
a) Countersinking such parts not less than 1/8 inch (3.2 mm) in the clear and then covering them with a waterproof insulating sealing compound which will not melt at a temperature of 65°C (149°F) or
b) Reliably securing such parts and insulating them from the mounting surface by means of a
barrier or the equivalent, or by means of through-air and over-surface spacings as specified in
Spacings, Section 8.