An underground mining operation such as a coal mine presents hazardous conditions for both machines and workers. An underground coal mine resembles a large construction project and frequently groups of workers are around or near high power electrical equipment. Mining equipment quite often requires large amounts of electrical power located near the underground excavation point which creates a need for large power transformers near the excavation point. These electrical power transformers combined with input, output, and control circuitry are combined in one enclosure called a power center. A power center is typically protected by a solid sheet-metal enclosure. The enclosure's main purpose is to protect the electrical components from dust, dripping water, and condensation, and dissipate heat. In addition, the enclosure must protect the electrical components from damage due to rock slides, rock falls, and cave-ins.
In addition to protecting the internal electrical components, enclosures are designed to increase mine safety. In the event of an internal electrical failure within the power center, the enclosure must retard the introduction of flames or sparks into the mining area where flammable materials may be ignited.
Currently, arc resistant enclosures in the industrial markets are designed to withstand the pressures and temperatures of gasses associated with an internal arcing fault and are configured to safely direct these gasses out of the roof of the enclosure away from personnel. This type of configuration is problematic for the underground mining industry where the ceiling of the mine is often only a few inches away from the top of the electrical enclosure. To make things worse, the ceiling and walls of the mine often contain flammable material such as coal. The surrounding air is also often times contaminated with coal dust and possibly explosive gases.