Electrical Metallic Tubing and Rigid Metal Conduit Quiz

Conditions for EMT Usage

• Electrical metallic tubing (EMT) should not be used in areas subject to corrosive fumes, as this can lead to deterioration.
• EMT is not suitable for abrasive or hazardous environments where it can be physically damaged or corroded.

Types of Fill and Hazardous Locations

• EMT should not be used with certain types of cable fill, particularly those that are moisture-laden or can retain water, leading to potential electrical hazards.
• According to the National Electrical Code (NEC) and the PEC, EMT is prohibited in Class I hazardous locations which involve flammable gases or vapors.

Classification of Hazardous Locations

• The third classification of hazardous location is Class III, which encompasses areas with combustible dust.

Impact of Cinders and Corrosion

• When cinders from coal-burning furnaces get wet, they can create a hazardous condition by producing a corrosive environment that can affect EMT integrity.

Flammable Gases and EMT

• The primary reason for avoiding EMT in areas with flammable gases and vapors is the risk of ignition and potential explosions due to the tubing not being designed to contain or prevent escape of ignition sources.

Consequences of Extreme Heat

• Exposing EMT to extreme heat can compromise its structural integrity, possibly leading to deformation or failure of the conduit system.

Mechanical Disturbance Effects

• Subjecting EMT to mechanical disturbances during or after construction can result in damage or misalignment, compromising the safety and reliability of electrical installations.