BlueCollarBench

Trades/Electrical

ElectricalTask EL-008apprenticeKnowledgeUS

Wiring a hallway light with a switch at each end using 14-2 from the panel and 14-3 between the switches.

Prompt as given to every model

Wiring a hallway light with a switch at each end using 14-2 from the panel and 14-3 between the switches. Which wires go where on the 3-ways?

Model answers

Pick up to two to compare side by side. Score chips fill in as the judge grades.

Laguna S 2.1Score —

Wiring a 3-Way Switched Hallway Light

You'll have:

  • 14/2 from panel: black (hot), white (neutral), bare (ground)
  • 14/3 between switches: black, red, white, bare

At the first switch (power source):

  • Connect the panel's black (hot) to the common terminal (usually black/dark screw)
  • Connect the panel's white (neutral) directly to the light fixture's white
  • Connect the panel's bare ground to the ground wire (14/3 bare) and switch's ground screw
  • From the 14/3 cable: connect black and red to the two traveler terminals (brass screws)

At the second switch:

  • The 14/3 black and red go to the two traveler terminals (brass screws)
  • The 14/3 white connects to the common terminal (black/dark screw)
  • The 14/3 bare ground connects to the ground screw

At the light fixture:

  • The 14/3 white connects to the light's white (neutral)
  • The switched hot comes from whichever traveler is active

Key point: The common terminal on each 3-way switch is the one that's electrically isolated from the travelers. It's typically a black or dark-colored screw, while travelers use brass screws.

Safety note: Always turn off power at the breaker and verify with a non-contact tester before working. If you're unsure about identifying the common terminal or don't have proper test equipment, hire a licensed electrician.

463 tokens · 10.0s

Judge rubric · pending

Not graded yet. Grading starts when the exam run completes.

Nemotron 3 Ultra 550BScore —

Power at Switch 1 (most common):

Switch 1 (where 14-2 from panel enters):

  • Black (hot from panel)Common (dark) screw
  • Red (14-3) → Brass traveler screw
  • Black (14-3) → Other brass traveler screw
  • White (14-3)Cap off (unused, mark with black tape if re-identified, but here it's just a spare)
  • All grounds → Green screw + box

Switch 2 (far end):

  • Red (14-3) → Brass traveler screw
  • Black (14-3) → Other brass traveler screw
  • White (14-3)Common (dark) screw (re-identified as hot with black tape) → runs to light fixture black
  • All grounds → Green screw + box

Light Fixture:

  • Black (from Switch 2 white) → Fixture black
  • White (from panel 14-2) → Fixture white
  • Ground → Fixture ground

Key Code Points (NEC 2020):

  • 404.2(C): Neutral required at each switch box. Run 14-3 (or 14-4) between switches to carry neutral to Switch 2. Your plan uses 14-3 but sends switched-hot back on the white. This violates 404.2(C) — no neutral at Switch 2.
  • Fix: Run 14-4 (or 12-4) between switches. Use red/black as travelers, white as neutral to Switch 2, blue (or black with tape) as switched-hot to light.
  • 300.14: 6" free conductor at each box.
  • 110.14(A): Proper splicing devices.

If power at light instead: Wiring differs. Confirm feed location first.

539 tokens · 4.8s

Judge rubric · pending

Not graded yet. Grading starts when the exam run completes.