ASME A17.5-2014 pdf download
ASME A17.5-2014 pdf download.Elevator and escalator electrical equipment.
3 Construction
3.1
Electrical components used in control equipment shall be suitable for the intended application and shall be
either
(a) certified to the requirements of the pertinent standards covering such components; or
(b) specifically evaluated for the intended use.
3.2
Components for electronic circuits such as solid-state devices (SCRs, diodes, etc.), resistors, and capacitors
for which there are no appropriate standards may be accepted as components based on examination
(quality of work, electrical spacings, etc.) and testing.
4 Enclosure construction
4.1 General
4.1.1
The enclosure of control equipment shall be constructed and assembled so that it will have the strength and rigidity necessary to resist the abuses to which it is likely to be subjected, without resulting in a hazard due to reduction of spacings, loosening or displacement of parts, or other serious defects.
4.1.2
An enclosure shall be constructed so as to reduce the risk of unintentional contact with enclosed electrical devices.
4.2 Thickness of cast-nictal enclosures for live parts
4.2.1
A cast-metal enclosure shall be made of malleable iron, die-cast metal, or permanent mould cast aluminum, brass, bronze, or zinc.
4.2.2
Other than as permitted in Clause 4.2.3, cast-metal enclosures shall be
(a) not less than 2.4 mm (0.094 in) thick for an area that is greater than 15 500 mm2 (24 in2) or that has a dimension greater than 150 mm (6 in);
(b) not less than 1 .6 mm (0.063 in) thick for an area that is 15 500 mm2 (24 in2) or less and that has no dimensions greater than 150 mm (6 in). The area limitation may be obtained by the provision of suitable reinforcing ribs subdividing a larger area; and
(c) not less than 3.2 mm (0.125 in) at reinforcing ribs, door edges, and unthreaded conduit entries.
4.2.3
Thicknesses less than those required by Clause 4.2.2 shall be permitted if the enclosure complies with the
following requirements:
(a) the crushing resistance test of Clause 19.11 of this Standard;
(b) the impact test of Clause 19.5 of this Standard, except that the energy required for the ball impact is 1 3.56 j (10.0 ft-lbf) for all sizes; and
(c) the conduit connection tests of CSA C22.2 No. 14 or UL 508.
4.3 Thickness of sheet-metal enclosures for live parts
4.3.1
Except as specified in Clause 4.3.2, the thickness of sheet-metal enclosures shall be not less than that specified in Tables 1 and 2, except that at the points at which a wiring system will be connected, uncoated steel shall be at least 0.78 mm (0.032 in) thick, zinc-coated steel at least 0.88 mm (0.034 in) thick, and non-ferrous metal at least 1.16 mm (0.045 in) thick.
4.3.2
The thickness of sheet metal for enclosures at points other than those at which a wiring system will be connected need not comply with the thickness requirements of Clause 4.3.1 if the enclosure complies with the compression and deflection test requirements in Clauses 19.8 and 19.9.
Note: Tables 1 and 2 are based on a uniform deflection of the enclosure surface for any given load concentrated at the centre of the surface, regardless of metal thickness.
4.3.3
With reference to Tables 1 and 2, a supporting frame shall consist of a structure of angles, channels, or folded rigid sections of sheet metal. This structure shall be rigidly attached to and shall have essentially the same outside dimensions as the enclosure surface and sufficient torsional rigidity to resist the bending moments that may be applied by the enclosure surface when it is deflected. A structure that is as rigid as one built with a frame of angles or channels is considered to have equivalent reinforcing. Constructions without a supporting frame shall be considered to include
(a) a single sheet with single-formed flanges or formed edges;
(b) a single sheet that is corrugated or ribbed;
(c) an enclosure surface loosely attached to a frame (e.g., with spring clips); and
(d) an enclosure surface having an unsupported edge.
5 Doors and covers
5.1
A part of the enclosure, such as a door or a cover, shall be provided with the means, such as latches or
screws, to firmly secure it in place. Snap-on covers of 0.1 m2 (155 in2) or less shall be permitted for signal
fixtures operating at 30 V rms, or 42 V peak, or less, provided they meet the test requirements of
Clause 6.16 of CSA C22.2 No. 14 or Clause 9 of UL 508.
5.2
Barriers shall be installed to prevent contact with live parts if inadvertent contact with bare live parts during normal service and adjustment operation is considered probable.
Note: Troubleshooting or the replacement of fuses is not considered a normal service adjustment operation with respect to control equipment, but the resetting of overload devices, adjustment of timers or switches, etc., are considered normal service operations.
5.3
Equipment enclosures containing any portion of the motor controller, that have markings in accordance with Clause 20.22 are designed to be located outside machinery spaces, machine rooms, control spaces, or control rooms and shall comply with all the following:
(a) access to the interior of the enclosure shall only be via door(s), or panel(s) that is (are) non-removable except with the use of tools or a key;
(b) door(s) or panel(s) shall require a key to open;
(c) door(s) or panel(s) shall remain mechanically attached to the enclosure when opened.