What is Class 1 Div 2?

As Transition Networks continues to expand its broad industrial portfolio we are beginning to offer Ethernet switches and media converters with a Class 1 Div 2 certification. Many of you may be wondering, “What does that mean?” I hope the following will clear this up.

Class 1 Div 2 by Definition

The Class 1 Div 2 nomenclature is an Underwriters Laboratory, North American certification.

Class 1 refers to locations in which flammable gases or vapors may be present in the air in sufficient quantities to be explosive or ignitable. Class II locations contain combustible dust.

The Div portion refers to whether the hazard is normal or abnormal. Normal means the hazard is expected to be present under normal operations. Abnormal indicates the hazard is due to a situation in which there has been a leak.

So for example, Class 1 Div 2 would be a situation in which ignitable concentrations of gases, vapors or liquids are present, but are contained (such as in pipe work, etc).

OK, what does that mean?

Class 1 Div 1 is an explosion-proof installation. This generally requires an instrument or equipment to be mounted within a pressurized enclosure. Class 1 Div 2 rated equipment, under intended operating conditions, is incapable of igniting flammable gas or vapor-air mixtures.

Class 1 Div 2 is very common in industries such as oil and gas refining and petrochemical manufacturing. As Ethernet continues to proliferate into more and more of the operations side of all types of organizations expect to see this becoming more common. Transition Networks, in recognition of this trend and the demand by our customers, is now offering Class 1 Div 2 certification on most of its fully hardened industrial products.

So what is the Benefit of Class 1 Div 2 certified products?

In one word: Safety. Our new Class 1 Div 2 certified industrial products have been independently tested by UL to ensure they meet the standard.

3 Responses to “What is Class 1 Div 2?”

  1. Delvin Tate Says:

    Can you tell me when class 1, class 2, Div 1 and 2 started in the US and other countries.

  2. siemens-Ag.com.Ua Says:


    My TN Connection » Blog Archive » What is Class 1 Div 2?…

  3. Dan Weber Says:

    In RE to “What is Class 1 Div 2?”

    Class 1 Div 2 – The National Electrical Code (NEC) definition of hazardous locations as those areas “where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids. “

    DIV 2 is defined as areas where the gas, vapor or mist would only be present under abnormal conditions (most often leaks under abnormal conditions) present under 10 hours/year or 0–0.1% of the time.

    Answered By: John Ragan, Product Management – Transition Networks

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