Put simply, it is the difference in a unit being explosion proof and one that is not.
What does explosion proof mean
To understand what is meant by explosion proof, we must first look at the context of the terms and the organization that defines them. The National Fire Protection Association (NFPA) wrote the standards for designing explosion and spark proof materials. More information can be found in the National Electric Code (NEC), also known as NEC 70 or NFPA70.
The NEC includes definitions for several types of protection techniques that are acceptable when designing products for use in hazardous (classified) locations. These are explosion proof, dust ignition proof, dust tight purged/pressurized, intrinsically safe, and hermetically sealed. The definitions contain the criteria to follow when designing components that will be installed in hazardous locations.
To be classified as explosion proof, an enclosure must be able to contain any explosion originating within its housing and prevent any possible ignition source from escaping and igniting vapors, gases, dust, or fibers in the surrounding atmosphere. Therefore, explosion proof, when referring to electrical enclosures, does not mean that it is able to withstand an exterior explosion. Instead, the enclosure is designed in such a way that if an explosion were to occur it would be contained, which prevents an exterior fire or blast.
Additionally, the equipment must meet the temperature requirements of the specific application in which it is to be installed. This means the operating temperature of the motor and its enclosure or other components cannot be greater than the lowest ignition or combustion temperature of the gases in the atmosphere where the component is to be installed. All components are labeled on their name plates with the distinct classification in which they have been tested and approved for.
At OTA we have the capability of designing any skid per the customer’s specifications. We understand what it is to be fully explosion proof and we take it very seriously. We take the time to discuss and explain what this means to the customer and how we will implement it for the desired application.