The cross-sectional area of conductors allowed in a seal must not exceed what percentage of the rigid metal conduit?

In hazardous locations, the management of potential ignition sources is crucial for maintaining safety. When it comes to sealing conductors in rigid metal conduit (RMC), there are specific guidelines to prevent any issues that could arise from sparks or heat generated by electrical connections.

The maximum allowable cross-sectional area of conductors within a seal must not exceed 25% of the cross-sectional area of the rigid metal conduit. This limitation ensures that there is sufficient space for heat dissipation and reduces the risk of creating a compressed area where gases or vapors could accumulate. By adhering to this percentage, the sealing practices can effectively contain any potential ignition sources, thereby enhancing safety within the hazardous environment.

The other percentages suggested in the answer choices represent smaller allowances, which do not conform with the established standards that prioritize safety in hazardous areas. The compliance with the 25% rule is part of a broader set of practices that align with national electrical codes and safety regulations in hazardous locations.