HOLT Electricians Practice Exam

How many fixture wires smaller than No. 14 can be omitted from calculations where they enter the box from a domed fixture?

1. 2

2. 3

3. 4

4. 5

The correct answer is: 4

In electrical calculations, particularly when dealing with fixture wires entering a box, the National Electrical Code (NEC) provides guidelines on how to account for smaller gauge wires. For wires that are smaller than No. 14, there is a specific rule that allows the omission of a certain number of these wires from the calculations intended to determine box fill. The correct response notes that up to four fixture wires smaller than No. 14 can be omitted when they enter the box from a domed fixture. This provision helps electricians design and install fixtures without being burdened by the cumbersome task of including every single smaller gauge wire in the box fill calculations, thus streamlining the process without compromising safety. This rule is based on considerations of thermal management and the physical dimensions of the wiring within a junction box, ensuring that boxes are not overloaded while still accommodating necessary connections. Understanding these nuances is essential for compliant and efficient electrical work, and being aware of these specific allowances helps streamline installations while ensuring adherence to safety standards.