Explosion Proof Duct Heater

explosion proof
In electrical engineering, a hazardous location is defined as a place where concentrations of flammable gases, vapors, or dusts occur.
Equpment designed in accordance with existing codes and standards such that it will operate in a specified hazardous environment without causing an explosion.
specification that indicates an enclosure is capable of withstanding and confining internal explosions.

duct heater
An electric-resistance or hot water heater mounted inside an air-delivery duct to provide supplementary heat to the delivered air.