NEC Commercial Electrical Practice Test

How is the maximum weight of a lighting fixture determined when supported by an outlet box?

1. By local building codes

2. By the size of the outlet box

3. By the type of fixture

4. By listing in the National Electrical Code

The correct answer is: By listing in the National Electrical Code

The maximum weight of a lighting fixture supported by an outlet box is determined by the listing in the National Electrical Code (NEC). The NEC provides guidelines and specifications regarding the construction, materials, and safety standards of electrical installations, including outlet boxes. These standards dictate load-bearing capabilities based on the outlet box design and the intended use. When a fixture is installed, it is essential to adhere to these regulations to ensure that the outlet box can safely support the weight of the fixture. The NEC listings take into account various factors, such as whether the box is designed for support of a fixture and its weight limits, which help to prevent potential hazards such as electrical failures, mechanical failures, or even fires. Local building codes and the size or type of a fixture may influence the installation process, but ultimately, the NEC provides the authoritative standard that ensures safety and compliance concerning the weight limits for fixtures supported by outlet boxes.