Journeyman Electrician Practice Exam

What is the minimum thickness of sealing compound required for a ½-inch rigid metal conduit in a Class I location?

1. 1/2 inch

2. 1/4 inch

3. 5/8 inch

4. 1 inch

The correct answer is: 5/8 inch

The minimum thickness of sealing compound required for a ½-inch rigid metal conduit in a Class I location is 5/8 inch. This requirement is established to ensure sufficient sealing against the intrusion of gases or vapors that may be present in hazardous locations. A properly sized sealing compound is crucial for maintaining the integrity and safety of the electrical installation by preventing the potential for explosive atmospheres. In a Class I environment, where flammable gases or vapors are present, it is critical to adhere to safety standards that dictate the appropriate measures for containment and sealing. A sealing compound that is less than the required thickness may not provide adequate protection, thus increasing the risk of ignition from electrical equipment. By specifying a thickness of 5/8 inch, the standards ensure that there is enough material to form a reliable barrier, thereby enhancing the safety of electrical systems in potentially hazardous environments.