Journeyman Electrician Exam (NEC)Wiring Methods and MaterialsMedium
A journeyman electrician is installing a new 480-volt, 3-phase motor circuit using 1 AWG THHN copper conductors in a 1-inch Rigid Metal Conduit (RMC). What is the minimum length of free conductor that must be left at each outlet, junction, and switch point for making splices or terminations?
- A8 inches
- B10 inches
- C4 inches
- D6 inches
Show answer & explanationAnswer & explanation
Correct answer: D. 6 inches
According to NEC Section 300.14, at least 6 inches (150 mm) of free conductor must be left at each outlet, junction, and switch point for splicing or termination. This applies to all conductors, including those for switching or connecting fixtures.
Why the other options are wrong
- A. 8 inches is more than required but acceptable, not the minimum.
- B. 10 inches is significantly more than required and would be acceptable but not the minimum.
- C. 4 inches is insufficient for making proper splices or terminations.
Free Conductor Length
The minimum length of conductor that must be left extending from an outlet, junction, or switch box to facilitate making splices or connections to devices.
- Minimum of 6 inches required.
- Measured from where the conductor emerges from raceway/cable sheath.
- Applies to all conductors at these points.
Memory trick: Give the wires 'six inches of freedom' for connections, don't be stingy.