Okay, let's break down the situation and analyze the electrical installation.

The Issues

The most glaring problem is the use of #14 AWG wire on a 20A circuit.

Why it's incorrect, and the code references



Overcurrent Protection and Conductor Ampacity (NEC 240.4(D)): This section of the National Electrical Code (NEC) addresses the protection of conductors by overcurrent devices (like your 20A breaker). It explicitly states that smaller gauge wires have maximum overcurrent protection. #14 AWG copper is rated for 15 amps #12 AWG copper is rated for 20 amps #10 AWG copper is rated for 30 amps Conductor Ampacity (NEC 310.16)

This table provides the allowable ampacities of insulated conductors under various conditions. It reinforces the ampacity limits mentioned above.

Consequences of Using #14 AWG on a 20A Circuit



Fire Hazard

The #14 AWG wire is not designed to safely handle 20 amps continuously. If a fault or overload occurs, the wire will overheat. The insulation can melt, leading to shorts, arcing, and potentially a fire.

Voltage Drop

While not as critical as the fire hazard, using undersized wire can also cause excessive voltage drop, especially over longer distances. This can lead to dimming lights or malfunctioning equipment.

Code Violation

This installation is a clear violation of the NEC and will likely fail inspection.

Liability

If a fire or other damage results from this incorrect wiring, the electrician (and potentially the building owner) could face significant liability.

Specific Breakdown of Your Scenario



Travelers

The fact that the #14 AWG is used for travelers in the 3-way/4-way switching system doesn't excuse the violation. The circuit is still protected by a 20A breaker, and any portion of that circuit (including the travelers) must be able to handle the full 20 amps if a fault occurs.

What Needs to Be Done


Replace the #14 AWG

The electrician must replace all of the #14 AWG wire used for the switch legs and travelers with #12 AWG or larger copper wire.2.

Verify All Wiring

It's crucial to verify that all wiring in the circuit is appropriately sized for the 20A breaker, not just the travelers.3.

Inspection

Ensure the corrected installation is inspected by a qualified electrical inspector.

In summary: The use of #14 AWG wire on a 20A circuit is a serious safety hazard and a violation of the NEC. It must be corrected immediately. The electrician needs to replace the wiring with the correct gauge wire (#12 AWG copper or larger). Flag for review