Chromalox Big Red Book

Technical

Technical Information NEMA Enclosures & Hazardous Location Heaters NEMA Enclosures for Classified Locations (Hazardous)

Immersion Heaters — Screw plug and flanged immersion heaters are available with terminal enclosures CSA or CSA NRTL/C certified for Class I, Groups B, C and D and Class II Groups E, F and G. Supplemental low-liquid level controls are required for maximum safety and equipment protection when immersion heaters are used in hazardous locations. 2

Chromalox Enclosures for Electric Heaters in Classified Locations Chromalox has terminal enclosures specifi- cally designed for use on electric heaters in- stalled in Classified (Hazardous) areas. These enclosures are identified as Type E2 and E3. Typical flange heaters with E2 hazardous area terminal enclosures are shown below.

The following are condensed descriptions of the NEMA enclosure types for Classi- fied (Hazardous) Locations. The Chromalox enclosures equivalent to the NEMA description are indicated. The Chromalox enclosure may not be indentical to the NEMA description due to modifications required to adapt the housing to heater configurations. The NEMA enclosure descriptions are not intended to be complete representations of the National Electrical Manufacturers Association standards for electrical enclosures. For complete details on NEMA enclosure requirements, refer to NEMA Std. No. 250. Type 7 Enclosures — are intended for indoor use in locations classified as Class I, Groups A, B, C and D as defined in the National Electri- cal Code. (Chromalox E2, E3 or Explosion Resistant enclosures.) 2 Type 8 Enclosures — are intended for indoor or outdoor use in locations classified as Class I, Groups A, B, C and D as defined in the National Electrical Code. (Chromalox E2 enclosures.) 2 Type 9 Enclosures — are intended for indoor use in locations classified as Class II, Groups E, F and G as defined in the National Electri- cal Code. (Chromalox E2, E3 or Explosion Resistant enclosures.) Type 10 Enclosures (MSHA) shall be capable of meeting the requirements of the Mine Safety and Health Administration, 30 C.F.R., Part 18.

EYS Seal

Circulation Heaters — Many water and oil circulation heaters are available with terminal enclosures CSA or CSA NRTL/C certified Class I, Groups B, C and D and Class II, Groups E, F and G. Supplemental controls are required for maximum safety and equipment protection when circulation heaters are used in hazardous locations Air Heaters — Blower type air heaters (CXH- A) are available for Class I, Division I, Groups C and D and Class II, Division I, Groups E, F and G with UL, UL-C, and/or CSA certification. Convection type air heaters (CVEP) are avail- able for use in Class I, Division I, Groups B, C and D hazardous locations. Convection type air heaters (FPEP and CEP) are available for use in Class I, Division I, Groups C and D and Class II, Division I Groups E, F and G. Specialty Products & Components — Chromalox has designed, manufactured and provided certification on a large number of specialty products for hazardous areas and other special applications. These products include UL Recognized Components (finned tubular elements), duct heaters and special aircraft ground support equipment. Contact your Local Chromalox Sales office for as- sistance in designing equipment or solving any unique electric heating application for hazardous areas.

Explosion Resistant Enclosure

Explosion Resistant Enclosure with EYS Seal

E2 enclosures are supplied with gaskets and are suitable for both indoor and outdoor loca- tions. E2 enclosures meet the moisture and explosion-resistant requirements for NEMA 4, 12, 7, 8 and 9 applications. E3 enclosures are usually not furnished with gaskets and are in- tended primarily for indoor and dry locations. See table below. Electric Heaters for Hazardous Locations Chromalox provides a wide variety of electric immersion and air heaters for use in hazard- ous locations. These heaters are listed by Underwriters Laboratories (UL) or certified by Canadian Standards Association (CSA). Heaters designed and certified for Class I or II Division I hazardous locations can be used in Division 2 areas in the same class.

Comparison of Specific Applications of Enclosures for Indoor Hazardous Locations

NEMA

Chromalox

Atmospheres Containing

Class Group

7

8

9

10

E2

E3

Acetylene

I I I I

A X X B X X C X X D X X

X 1,2

Hydrogen, Manufactured Gas Diethel Ether, Ethylene, Cyclopropane

X 1,2

X X X X X X X X X X X X

Gasoline, Hexane, Butane, Naptha, Propane, Acetone Toluene or Isoprene

Metal Dust

II II II

E F G G

X X X X

Carbon Black, Coal Dust, Coke Dust

Flour, Starch, Grain Dust

Fibers, Flyings

III

Methane with or without Coal Dust

MSHA

X

1. Requires seals in the conduit adjacent to the terminal enclosure. 2. For EMT and MT styles, Class 1 Group B; Divisions 1& 2, consult factory.

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