UL 60079-6-2020 pdf download

UL 60079-6 2020 pdf download.Explosive atmospheres – Part 6: Equipment protection by liquid immersion “o”.
3.5 maximum permissible protective liquid level maximum level that the protective liquid can attain in normal service, taking into account the effects of expansion from the worst-case filling condition specified by the manufacturer to the condition of full load at maximum ambient temperature for which the equipment is designed 3.6 minimum permissible protective liquid level minimum level that the protective liquid can attain in normal service taking into account the effects of contraction from the worst-case filling condition to the condition of de-energization at minimum ambient temperature 3.7 disconnector mechanical switching device which provides, in the open position, an isolating distance in accordance with specified requirements Note 1 to entry: A disconnector is capable of opening and closing a circuit when either negligible current is broken or made, or when no significant change in the voltage across the terminals of each of the poles of the disconnector occurs. It is also capable of carrying currents under normal circuit conditions and carrying for a specified time currents under abnormal conditions such as those of short circuit. [SOURCE: IEC 60050-441:1984, 441-14-05] 3.8 switching device device designed to make or break the current in one or more electric circuits [SOURCE: IEC 60050-441:1984, 441-14-01] 3.9 safety device device intended for use inside or outside explosive atmospheres but required for or contributing to the safe functioning of equipment and protective systems with respect to the risks of explosion 3.10 tap selector device designed to carry, but not to make or break current, used in conjunction with a diverter switch to select tapping connections [SOURCE: IEC 60050-421:1990, 421-11-02]
4.2.2 Requirements for Level of Protection “ob” Electrical circuits and components, when liquid immersed in accordance with this standard, are considered to be not ignition capable in normal operation and during expected malfunctions, and shall be assigned a Level of Protection “ob” (EPL Gb or Mb). A liquid level indication according to 4.7 is required. Switching devices protected by liquid immersion level of protection “ob” shall comply with the following additional requirements: a) When a sealed enclosure is employed, the enclosure shall comply with the overpressure test in 6.1.1 using four times the prescribed pressure. b) Electrical equipment containing switching devices operated in the protective liquid, rated at 2 kVA per contact or less, are permitted without further test. Where the switching device is rated above 2 kVA per contact, neither pressure increases nor excessive decomposition products shall invalidate the type of protection as demonstrated by tests in accordance with 6.1.5. c) The equipment shall be suitable for a prospective short circuit current of 32 kA unless marked with a lower value. 4.2.2DV.1 DR Modification ofClause 4.2.2, thirdparagraph to addthe following NOTEafter item c): NOTE The National Electrical Code®, (NEC®), ANSI/NFPA 70, may limit the use of increased safety terminations to 10 kA available short circuit current.
4.4 Creepage and clearance Electrical circuits and components intended to be immersed in the protective liquid shall meet the relevant industrial requirements for creepage and clearance distances in air before being immersed in the protective liquid. If the relevant industrial standard gives options for pollution degree, pollution degree 2 shall be assumed. 4.5 Liquid containment enclosures 4.5.1 General The chemical resistance against the protective liquid shall be documented by the manufacturer. NOTE It is not a requirement of this standard that conformity to the chemical resistance against the protective liquid be verified. The enclosures shall be subjected to the type tests as specified in Clause 6 for sealed and unsealed enclosures respectively. Connection bushings provided for termination of the electrical conductors shall be considered as part of the enclosure and subject to the requirements of this clause.UL 60079-6-2020 pdf download.