What Are Explosion-Proof Enclosures, and Why Should We Care?

Explosion-proof enclosures are simple boxes containing electrical plugs, knobs, switches, and other components that can contain any explosion or spark within the box without exposing it to the outside environment. Industrial facilities that operate in hazardous environments require these enclosures because standard electrical enclosures are not designed to contain explosions. These robust, heavy-duty explosion-proof cabinets can reduce the risk of explosion in environments with flammable vapor, gases, and dust, such as oil refineries, chemical plants, fuel servicing sites, feed mills, and plastic/fireworks factories.

Why Use Intrinsically Safe or Explosion-Proof Cabinets?

It’s important to find certified explosion-proof and intrinsically safe cabinets to store electrical components like knobs and switches if you’re using them in a space that the National Fire Protection Association (NFPA) has classified as hazardous.

Similarly, Explosion Proof and IS cabinets stop explosions or infernos from spreading from an internally exploding device to its surroundings. As a result, workers in industrial facilities that are prone to explosions will have a safer working environment.

What Is the Difference Between Explosion Protection and IS Enclosures?

The primary distinction between an Explosion Proof enclosure and an IS enclosure is that the former is a containment strategy, whereas the latter is a prevention strategy. In other words, intrinsic safety refers to preventing the possibility of ignition or explosion rather than merely containing an existing issue.

IS design places more emphasis on a component’s electrical architecture. The goal is to keep the device’s circuit current, voltage, and temperature as low as possible during operation.

An intrinsically safe junction box, for instance, is resistant to overheating and is suitable for use in industrial facilities that are subject to high operating temperatures. Its circuitry does not produce sparks or arcs that could ignite a gas or vapor explosive mixture.

Types of Explosion Proof Enclosures

Explosion-proof enclosures come in a variety of forms, including:

Junction boxes: These are perfect for rigid conduit systems in explosive environments, such as gas stations. They are equipped with heavy-duty, rain-tight explosion-proof enclosures to prevent internal explosions because they contain electrical components and wiring that could spark or short.

Cabinets: Explosion-proof cabinets store hazardous materials like flammable liquids and chemicals. They have a number of fire safety features, including strong steel enclosures for containing explosions and air vents for preserving safe interior temperatures.

Intrinsically safe barriers: These barriers regulate the energy supplied to electrical equipment in potentially hazardous environments. These systems stop combustible materials from igniting by limiting the energy supply to circuits. Isolated barriers, for instance, shield control circuits from dangerous power surges that could set off explosive mixtures in the vicinity.

Different Ratings That Are Relevant to Explosion-Proof Enclosure Design

Explosion-proof or intrinsically safe barriers, junction boxes, and other containment enclosures must be designed and built in accordance with the guidelines outlined in the NEC hazardous area classifications. Manufacturers, on the other hand, may voluntarily comply with relevant NEMA ratings. The following NEMA/NEC classifications and ratings apply to Explosion Proof / Intrinsically Safe enclosures:

NEMA 1

The standard applies to general-purpose enclosures used indoors. The primary goal of these storage boxes is to keep electrical components out of contact with potentially explosive gas, dust, or vapor mixtures.

NEMA 7

These enclosures are intended for use in locations designated by the NEC as Class 1, Group A, B, C, or D. They are designed to withstand pressure caused by an internal gas explosion. They also reduce the impact of any such explosive combustion so that it cannot ignite a flammable gas-air mixture in the immediate vicinity.

NEMA 9

Explosion-proof enclosures intended for use in NEC locations like Class 2, Groups E, or F must adhere to the type 9 standard. Their goal is to keep dust out of the enclosure. Any housed heat-generating component should not cause external surface temperatures to rise to the point where combustible mixtures in the surrounding environment ignite.

IEC Zoning: International Electro-Technical Code

The IEC classifies areas as hazardous based on the potential presence of flammable substances and their properties. It also accounts for the potential presence of combustible gases, vapors, or dust.

The Final Note: 

To reduce various types of risks, such as combustible gases, vapors, and dust in their operating environment, many industrial facilities store electrical equipment inside explosion-proof enclosures. In order to avoid explosions and fire accidents that could endanger personnel and cause property damage, these organizations are increasingly upgrading their hazardous area-certified hardware to intrinsically safe standards. 

Are you looking to purchase explosion-proof enclosures for use in hazardous areas? Contact Maes Lighting to order high-quality explosion-proof enclosures, fittings, and receptacles made in the USA by Akron.