HOLT Electricians Practice Exam

For conduits entering explosion-proof enclosures, what is the maximum conduit size without sealing requirements?

1. 1 inch

2. 1 ½ inches

3. 2 inches

4. ¾ inch

The correct answer is: 1 ½ inches

In the context of explosion-proof enclosures, specific regulations dictate the requirements for conduits entering these areas to prevent the possibility of an explosion due to the ignition of flammable gases or vapors. According to the National Electrical Code (NEC) and related guidelines, conduits that are up to a certain diameter do not require sealing if they meet particular criteria. The maximum size of the conduit that can enter an explosion-proof enclosure without sealing requirements is 1 ½ inches. This specification is designed to balance the need for safety by preventing potential ignition sources while allowing for the installation of necessary electrical conduits. The size restriction ensures that if any flammable substance does enter through the conduit, the likelihood of causing a spark or ignition is minimized. Conduits larger than this size would need to have sealing methods in place to prevent gas or vapor from entering the enclosures, which is critical for maintaining the integrity of explosion-proof installations. Thus, choosing 1 ½ inches adheres to safety regulations while promoting efficient installation practices in potentially hazardous environments.