Can underfloor boxes be used without covers?

Underfloor boxes must always have proper covers to ensure safety and limit hazards. This requirement stems from the National Electrical Code (NEC) which mandates that electrical boxes, including those located under floors, need to be securely covered to prevent accidental contact with electrical connections, protect against dust and debris, and maintain the integrity of the electrical system. Exposed live parts can create a serious risk of electrical shock or fire hazards.

The use of covers also helps to sustain the functionality of the box. Without covers, moisture and other environmental factors can lead to degradation of the components inside, which may compromise the electrical performance or safety in the long run. Therefore, keeping underfloor boxes covered is essential for both user safety and compliance with NEC standards.