ASME A17.5:2014 pdf free download

ASME A17.5:2014 pdf free download
ASME A17.5:2014 pdf free download.Elevator and escalator electrical equipment
16.9 Spacings between traces of different potentials on a printed circuit board are not required to comply with Table 1 2 when all of the following conditions are met:
(a) The spacings are used in a circuit where power is limited by a transformer, rectifier, voltage divider, or similar device that derives power from a primary circuit, and where the short-circuit limit between conductors of the secondary circuit or between conductors and ground is 1 500 VA or less.
Note: The short-circuit volt ampere limit is the product of the open-circuit volts and the short-circuit amperes, and these are rms values in an ac circuit.
(b) The spacings are not used for circuits containing electrical protective devices as defined in ASME A1 7.1 /CSA B44, ASME A1 8.1 , and CSA B355.
(c) The printed circuit board has a flammability rating of V-0.
(d) The printed circuit board base material has a minimum comparative tracking index (CTI) of 1 00 V.
(e) The traces do not involve separate isolated circuits.
(f) The equipment complies with the Printed Wiring Board Abnormal Operation Test specified in CSA C22.2 No. 1 4 or UL 508.
16.27.4 In conducting evaluations in accordance with the requirements in CSA C22.2 No. 0.2 or ANSI/UL 840, the following guidelines shall be used:
(a) Unless specified elsewhere in this Standard, the pollution degree shall be considered to be pollution degree 3.
(b) Equipment that operates in the direct line of the source of power to the load equipment shall be considered to be Overvoltage Category II.
(c) Pollution degree 2 may be considered to exist on a printed circuit board between adjacent conductive material covered by any coating that provides an uninterrupted covering over at least one side and the complete distance up to the other side of conductive material.
(d) Any printed circuit board that complies with the requirements in UL 796 shall be considered to provide a minimum comparative tracking index (CTI) of 1 00. The materials listed in Clause 1 1 .1 of this Standard or any material that complies with the requirements of Section 22 of UL 796 shall be considered to provide a minimum CTI of 1 75.
(e) In order to fulfill the requirements for coatings of printed circuit boards used to achieve pollution degree 1 in accordance with CSA C22.2 No. 0.2 or ANSI/UL 840, a coating shall comply with the requirements of Section 47 of UL 746C.
(f) Pollution degree 1 may also be achieved at a specific printed circuit board location by application of at least a 0.79 mm (0.031 in) thick layer of silicone rubber or by potting, without air bubbles, in epoxy or potting material.
(g) The evaluation of clearances to determine equivalence with through-air spacing requirements may be conducted in accordance with Clause 4.1 of CSA C22.2 No. 0.2 or ANSI/UL 840, Paragraph 4, regarding Clearance A (Equivalency).
(h) The evaluation of clearances and creepage distances shall be conducted in accordance with the requirements in Clauses 4.2 and 4.3 of CSA C22.2 No. 0.2 or Paragraph 5 and requirements on creepage distance in ANSI/UL 840.