If a three-way switch lighting circuit works from one switch and not the other, the most probable cause is

If a three-way switch lighting circuit works from one switch and not the other, the most probable cause is

• A. The traveler wires are not on proper connections
• B. The neutral is loose
• C. The breaker is tripped
• D. The load is shorted

Answer: (A)

In a three-way lighting circuit, two switches control the same light using two traveler wires that run between the switches and two common terminals: one common ties to the hot feed, the other to the load. The traveler wires carry the signal that lets either switch complete or break the circuit path, depending on the switch positions. When everything is wired correctly, you can turn the light on or off from either switch because the two switches cooperatively alternate which traveler path is live. If the light works from one switch but not the other, the most likely issue is with the traveler wires not being connected properly. If a traveler conductor is loose or misconnected at one end (not on the traveler terminals), the switch at that end can fail to establish a proper path to the load, making the other switch seem unable to control the light. The neutral being loose would typically affect the return path for the load and could cause the light not to operate independently of switch position. A breaker trip or a shorted load would disrupt power to the entire circuit, so the symptom would be power loss at all locations, not just one switch. To fix it, verify that both traveler wires are securely and correctly connected to the traveler terminals on both switches, with the hot feed on the appropriate common of the first switch and the load on the common of the second switch.

In a three-way lighting circuit, two switches control the same light using two traveler wires that run between the switches and two common terminals: one common ties to the hot feed, the other to the load. The traveler wires carry the signal that lets either switch complete or break the circuit path, depending on the switch positions. When everything is wired correctly, you can turn the light on or off from either switch because the two switches cooperatively alternate which traveler path is live.

If the light works from one switch but not the other, the most likely issue is with the traveler wires not being connected properly. If a traveler conductor is loose or misconnected at one end (not on the traveler terminals), the switch at that end can fail to establish a proper path to the load, making the other switch seem unable to control the light. The neutral being loose would typically affect the return path for the load and could cause the light not to operate independently of switch position. A breaker trip or a shorted load would disrupt power to the entire circuit, so the symptom would be power loss at all locations, not just one switch. To fix it, verify that both traveler wires are securely and correctly connected to the traveler terminals on both switches, with the hot feed on the appropriate common of the first switch and the load on the common of the second switch.