Temperature ClassĪ temperature class for junction box is utilized to assign the most extreme operating temperature on the surface of the equipment, which ought to be not exactly ignition temperature of the surrounding, potentially hazardous atmosphere.Īs per IEC-60079-10, the junction box located in the field should be suitable for hazardous areas with gas group II and temperature class of T3 as a minimum. EarthingĪs per IEC-60529, Earth studs should be welded to the enclosure wall to maintain the integrity of the IP rating. Mostly gland plates are made up of SS316L which provides excellent corrosion resistanceĪs per IEC-60423, it is recommended to use SS316L as the gland plate material.Īs per IEC-62444, Cable glands should be made up of nickel-plated brass. Gland plates are the most commonly used medium for cable entry. On Ex ‘e’ certified instrument junction box, cable entry should be at the bottom and sides which should maintain the certification and IP rating of the enclosure.Īs per EN-60079-0, cable entries should maintain the degree of ingress protection IP & the Ex rating.Īs per EN-60079-10, all unused entries in the junction box should be sealed. The screw mechanism limits the minimum physical size of the terminal. We usually select terminal types according to IEC-60947. Spring Cage Type or Pin Type terminals are most commonly used because of vibration-proof connection, high strength, easy installation, and good electrical conductivity. They are Screw type & Pin / Spring Cage type. Mainly two types of terminals are used in junction boxes. Normally in all industries, they usually prefer junction boxes with a minimum IP65. Whereas, for outdoor areas, a minimum IP56 is required to withstand severe conditions. For indoor areas, usually, IP21 & IP 44 are used because of their low-security level. We have to choose the IP rating of equipment by studying the location where we have to install that. Ingress Protection is detailed in international standard IEC-60529. Ingress Protection (IP) Rating provides protection of equipment against certain external influences such as dust, water, accidental contact, intrusions, and protection against direct contact. CRCA steel is also used as a material for manufacturing junction boxes for non-hazardous small scale industries Ingress Protection Rating (IEC-60529) SS316L & GFRP are widely used materials for both indoor & outdoor instrument junction boxes. Glass Fiber Reinforced Polymer (GFRP) is the widely used material for outdoor areas due to its high resistance to contamination from oils & its excellent mechanical properties & life expectancy. Materials with good corrosion resistance, high yield, high creep strength and tolerance to high ambient temperature is used for manufacturing junction boxes for outdoor areas that are exposed to changing environmental conditions. The most commonly used junction boxes in the offshore platforms are Ex e “increased safety” & Ex d “flameproof”. IECEx Certification is based on International Standard IEC-60079 Series & ATEX Directive is based on European Union (EU) Standard. Type SS316L is usually preferred because Type 303 & 304 are more subjected to pitting – type corrosion (API RP 14F & API RP 14FZ).Īs per API 14FZ, SS316L is capable of achieving ingress protection enabling those instrument junction boxes to be reasonable for use in hazardous areas and can be certified under ATEX Directive & IECEx Certification scheme. In offshore structures, the majority of instrument junction boxes are manufactured using stainless steel. IEC-61892 (Mobile & Fixed Offshore Units, Electrical Installations) Junction Box Material Selection.IEC-60423 & IEC-62444 (Design, Construction & Selection of Gland plates & Cable Glands).IEC-60079-14 (Electrical Installations design, selection & erection).IEC-60079-7 (Equipment Protection by Increased Safety ‘e’.IEC-60079-10.1.:2009 (Explosive Atmosphere – Classification of areas explosive, gas atmosphere).IEC-60079 (Equipment – general requirements).API RP 14F & API RP 14FZ (Design, Installation & Maintenance for Fixed & Floating Offshore petroleum facilities for Unclassified & class1, zone0, zone1 & zone2 locations.).The following codes and standards are applicable while selecting a junction box. Ambient Temperature Codes and Standards.Junction Box Selection Factorsįactors that have to be considered for selecting Junction Box are as follows. The selection of instrument junction boxes shall be governed by the specific electrical application and by the areas in which the junction boxes are installed.Ī junction box should have certification to exhibit proper hazardous area protection & ingress protection IP.
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