What is the maximum size conductor permitted for devices using the "push-in" termination method?

The maximum size conductor permitted for devices that use the "push-in" termination method is indeed 14 AWG copper (solid). This limitation is specified due to the design and mechanical properties of push-in terminals, which can securely hold smaller gauge wires while minimizing the risk of damage or failure in connection integrity.

Push-in connections are designed for ease of use, allowing users to quickly insert wires without the need for additional tools. However, larger gauge wires, such as 12 AWG or 10 AWG, may not fit properly into the terminals or could exceed the mechanical grip strength losses, leading to poor connections. This can result in increased resistance and potential overheating, which can become a serious safety hazard.

By setting the maximum to 14 AWG for push-in terminations, the electrical codes and safety standards prioritize both the effectiveness of the connection and the safety of the electrical installations. Smaller AWG sizes provide a balance that ensures adequate electrical conductivity while maintaining a secure physical connection within the limitations of push-in designs.