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KILLARK INTRODUCTION

HAZARDOUS LOCATION DATA

Dust-Tight equipment is designed to prevent combustible dust from entering apparatus and to prevent any hot particles or sparks generated within the unit from passing from to the outside of the enclosure through its joints. The objective is to prevent the ignition of combustible dust suspended in the air or the ignition of layers of dust on the equipment from being ignited by materials escaping the enclosure. This heat can, as in explosion proof apparatus, result from normal or abnormal equipment operation, or arcing ground faults. Since the combustible materials are kept outside the unit, the enclosure is not expected to withstand an internal explosion and it’s physical strength needs only to be sufficient to withstand abuse. The unit must also withstand internal arcing ground faults for enough time for the circuit over-current protection to open the circuit and stop the arcing. The types of joints used in Dust-Tight products are similar to explosion-proof equipment, but the requirements are not as rigid. These joints are needed to prevent dust from entering the enclosure and hot particles from exiting under fault conditions. Since the ignition temperature of dusts is usually lower than that of gases and vapours, the control of external surface temperatures is more rigorous in dust-tight equipment than in explosion proof equipment. Dust layers on the equipment can prevent dissipation of heat generated within the equipment and increase the surface temperature even under normal operating conditions. EQUIPMENT DUST IGNITION PROTECTION BY ENCLOSURE “t” (Also “Ex ta”, “Ex tb” and “Ex tc”) Much like North American dust tight requirements the objective of the IEC version is to keep dust from entering the enclosure. The testing parameters and material are different. ENVIRONMENTAL PROTECTION The following are environmental protection designations, which are specified in addition to electrical or hazardous location requirements. Many people refer to the NEMA (National Electrical Manufacturers Association) when requesting enclosure types, however the NEMA 250 Standard is for reference only. In North America products are tested to the harmonized with UL 50/ CSA C22.2 No. 94 standard and identified as Enclosure Type followed by the appropriate number as indicated below.

Type 1 Enclosures Intended for indoor use primarily to provide a degree of protection against limited amounts of falling dirt. Type 2 Enclosures Intended for indoor use primarily to provide a degree of protection against limited amounts of falling water and dirt. Type 3 Enclosures Intended for outdoor use primarily to provide a degree of protection against rain, sleet, windblown dust; and damage from external ice formation Type 3R Enclosures Intended for outdoor use primarily to provide a degree of protection against rain, sleet; and damage from external ice formation, and must have a drain hole. Type 3S Enclosures Intended for outdoor use primarily to provide a degree of protection against rain, sleet, windblown dust; and to provide for operation of external mechanisms when ice laden. Type 4 Enclosures Intended for indoor or outdoor use primarily to provide a degree of protection against windblown dust and rain, splashing water, hose directed water; and damage from Intended for indoor or outdoor use primarily to provide a degree of protection against corrosion, windblown dust and rain, splashing water, hose directed water; and damage from external ice formation. Type 5 Enclosures Intended for indoor use primary to provide a degree of protection against settling airborne dust, falling dirt, and dripping non corrosive liquids. Type 6 Enclosures Intended for indoor or outdoor use primarily to provide a degree of protection against hose directed water, the entry of water during occasional temporary submersion at a limited depth; and damage from external ice formation. external ice formation. Type 4X Enclosures

Type 6P Enclosures Intended for indoor or outdoor use primarily to provide a degree of protection against hose-directed water, the entry of water during prolonged submersion at a limited depth; and damage from external ice formation. Type 12 Enclosures Intended for indoor use primarily to provide a degree of protection against circulating dust, falling dirt, and dripping non-corrosive liquids. Type 12K Enclosures Intended knockouts are intended for indoor use primarily to provide a degree of protection against circulating dust, falling dirt, and dripping non corrosive liquids. Type 13 Enclosures Intended for indoor use primarily to provide a degree of protection against dust, spraying of water, oil, and non-corrosive coolant. DEFINITIONS REFERRING TO NEMA REQUIREMENTS FOR occasionally appear on specifications and product literature however, they are not included in the UL 50/CSA C22.2 No. 94 Standard. These NEMA types are specific to the US only. NEMA 7 Enclosures Intended for indoor use in locations classified as Class I, Groups A, B, C, or D, as defined in the NEC. NEMA 8 Enclosures Intended indoor or outdoor use in locations classified as Class I, Groups A, B, C, or D, as defined in the NEC. NEMA 9 Enclosures Intended for indoor use in locations classified as Class II, Groups E, F, and G, as defined in the NEC. NEMA 10 Enclosures Are constructed to meet the applicable requirements of the Mine Safety and Health Administration. (MSHA) HAZARDOUS LOCATIONS The following NEMA type enclosures

H10

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