Journeyman Electrician Exam (NEC)Equipment and DevicesMedium
A technician is installing a new 120-volt, 60-watt incandescent luminaire in a dwelling unit hallway. The fixture is rated for a maximum of 75 watts. According to NEC 410.16(A)(1), what is the minimum required free conductor length that must be left in the outlet box for making connections?
- A250 mm (10 inches)
- B100 mm (4 inches)
- C200 mm (8 inches)
- D150 mm (6 inches)
Show answer & explanationAnswer & explanation
Correct answer: D. 150 mm (6 inches)
NEC 410.16(A)(1) refers to the general requirement in NEC 300.14 for minimum conductor length. NEC 300.14 states that at least 150 mm (6 inches) of free conductor must be left at each outlet, junction, and switch point for splices or the connection of luminaires or devices.
Why the other options are wrong
- A. 250 mm (10 inches) is significantly more than the minimum required.
- B. 100 mm (4 inches) is less than the minimum required length.
- C. 200 mm (8 inches) is more than the minimum but not the specified minimum.
Minimum Free Conductor Length
The minimum length of conductor required to extend from an outlet box, junction box, or switch box to allow for proper splicing or connection of devices or luminaires.
- NEC 300.14 specifies 150 mm (6 inches).
- Ensures adequate room for making safe and reliable connections.
- Applies to all conductors entering the box.
Memory trick: Box Wires: Six Inches, No Less Than That.