Cold Weather Catalog - Chromalox Precision Heat and Control

TechnicalTechnical InformationNEMA Enclosures & Chromalox EquivalentsNEMA Enclosures forNon-Hazardous AreasThe National Electrical Manufacturer’s Association(NEMA) publishes a classifi cationsystem for electrical enclosures. The NEMAclassifi cation or type indicates the exposureor environment for which the enclosure wasdesigned. While Chromalox E1, E2, E3 andE4 enclosures are designed for applicationssimilar to the NEMA types, they are not identicaldue to modifi cations required to adapt thehousings to heater confi gurations. Condenseddescriptions of the NEMA non- hazardousenclosure types are listed below with the Chromaloxequivalents indicated. The condenseddescriptions are not intended to be completerepresentations of the National ElectricalManufacturers Association standards forelectrical enclosures. For complete details onNEMA enclosure requirements refer to NEMAStd. No. 250.Type 1 Enclosures — are for indoor use inlocations where unusual service conditionsdo not exist. Intended primarily to provideprotection against contact with the enclosedequipment and limited amounts of falling dirt.(Chromalox E1 or General Purpose enclosures.)Type 2 Enclosures — are for indoor useproviding protection against limited amountsof falling water and dirt.Type 3 Enclosures — are for outdoor useproviding protection against windblown dust,rain, and sleet and damage from external iceformation on the enclosure.Type 3R Enclosures — are similar to Type 3except Type 3R provides protection againstfalling rain.Type 3S Enclosures — are for outdoor useprotecting against windblown dust, rain, andsleet and providing for operation of externalmechanisms when ice laden.Type 4 Enclosures — are for indoor oroutdoor use providing protection againstwindblown dust and rain, splashing water,and hose-directed water and remain undamagedby the formation of ice on the enclosure.(Chromalox E4 Moisture Resistant or E2Moisture and Explosion Resistant enclosures.)Type 4X Enclosures — are similar to Type 4except Type 4X also protects againstcorrosion.Type 5 Enclosures — are for indoor use andprotects against dust and falling dirt.Type 6 Enclosures — are for indoor oroutdoor use providing protection against theentry of water during temporary submersionat a limited depth and remain undamaged byice on the enclosure.Comparison of Specific Applications of Enclosures for Non-Hazardous LocationsType 6P Enclosures — aresimilar to Type 6 except Type 6Pprotects against the entry ofwater during prolonged submersionat a limited depth.Type 12 Enclosures — are intendedfor indoor useproviding protection againstdust, falling dirt and drippingnon-corrosive liquids.(Chromalox E2 and E4enclosures.)Type 12K Enclosures (knockouts)— are similar to Type 12 exceptthey are provided with knockouts.Knockouts only permitted in eitheror both the top or bottom walls.Type 13 Enclosures — are forindoor use providing protectionagainst lint, dust, spraying of water,oil and non-corrosive coolant.(Chromalox E2 enclosures maybe used.)The table below lists a comparisonof the characteristics of NEMA andChromalox enclosures for Non-Hazardous areas.Note — For Classifi ed (Hazardous)Location enclosures, refer toNEMA Enclosures and HazardousLocation Heaters elsewhere in thissection.Provides a Degree of Protection AgainstType of Enclosure Chromalox ®the following Environmental Conditions 1 2 3 3R 3S 4 4X 5 6 6P 11 12 12K 13 E1 E2 E3 E4Incidental contact with the enclosed equipment X X X X X X X X X X X X X X X X X XFalling dirt X X X X X X X X X X X X X X XFalling liquids and light splashing X X X X X X X X X X X XDust, lint, fi bers and fl yings — Not Class III X X X X X X X X X X XHosedown and splashing water X X X X X XOil and coolant seepage X X X X X XOil or coolant spraying and splashing X XWindblown dust X X X X X X X X XRain, snow and sleet X X X X X X X XSleetXCorrosive agents X X XOccasional temporary submersion X XOccasional prolonged submersionX212