When a conduit passes through an exterior wall and enters a panel mounted on the interior, are seals or plugs required?

When a conduit passes through an exterior wall and enters a panel mounted on the interior, it is essential to use seals or plugs to provide protection against moisture and environmental elements. This requirement is primarily rooted in the National Electrical Code (NEC), which outlines that any point where electrical raceways, such as conduits, penetrate an external wall must be effectively sealed. This sealing helps to prevent water ingress, which could lead to electrical shorts, equipment damage, and potential safety hazards.

By implementing seals or plugs, installers ensure that the interior panel and associated electrical systems are safeguarded from external weather conditions. This practice also helps maintain the integrity of the electrical system and enhances overall safety by reducing the risk of corrosion and deterioration over time. Therefore, the correct answer emphasizes the importance of using proper sealing methods in these scenarios, confirming compliance with safety standards and effective installation practices.