AC Din Rail SPD for Hazardous Locations

Hazardous Locations Defined

Hazardous Locations consist of areas where there is the potential for fire or explosion due to electrical equipment that is in operation in this area with a reaction to flammable or ignitable gases, liquids, vapors, combustible dues, fibers or flying's. The need for Explosion-Proof equipment then arises due to this potential for fire or explosion.

The National Electric Code (NEC) along with the National Fire Protection Association (NPFA) and Underwriters Laboratories (UL) have published a guide along with codes that classify hazardous areas into class, divisions and zones.

NEC Hazardous Location Definitions

The "Combustion" or "Fire" Triangle is used to classify Hazardous Locations in the Explosion-Proof Industry. A source of fuel (explosive gases, liquids, or vapors), source of ignition (fire, spark, or explosion) and oxygen must be present in the appropriate consistencies for an explosion to occur. Explosion-proof enclosures and products are required to prevent these three ingredients from mixing in such a way that would generate an explosion.
NFPA 70 defines Hazardous Location in terms of Classes, Divisions and Groups. They chart below summarize the NFPA 70 NEC Hazardous Location definitions.

Class I, Division 2, Surge Protection Requirements

The NEC Article 501 specifically addresses requirements for the Class I location. Section 501.35 requires that surge arrestors and surge protective devices (SPD) shall be nonarcing, such as metal-oxide varistors (MOV) sealed type. As such, the surge protector device (SPD) can be mounted inside a general-purpose enclosure. Surge protective devices (SPD) utilizing spark producing surge protection components are required to be installed into an enclosure identified for the location. The NEC also specifies that surge protective devices utilized in Class 1, Division 2 environments shall be evaluated and listed to UL121201.

Recommended AC Surge Protective Device deployed into Class I, Div. 2, Group A, B, C or D Hazardous Locations

CITEL's single pole DS71US-Ex range have been certified to UL 121202 and are listed under UL file E527348-Surge Protective Devices for use in Hazardous Locations-(VZCH, VZCH7). The products listed below are recommended for AC Surge Protection installed into a Class 1, Div. 2, Groups A, B, C, D rated enclosure. The DS71US-Ex Din Rail SPD feature compact size, easy installation, visual status indicator and safe end-of-life disconnection.

Part Number	Circuit	MCOV	Temp.Code	Picture
DS71US-210-Ex	120VAC	210VAC	T5
DS71US-275-Ex	120VAC	275VAC	T5
DS71US-420-Ex	277VAC	420VAC	T5
DS71US-460-Ex	347VAC	460VAC	T5

References