When connecting wires from a panel to a control device outside the panel, what must be avoided?

The correct answer highlights an important safety and functionality requirement in electrical system installations. When connecting wires from a panel to a control device, using a terminal block is often considered good practice. Terminal blocks provide a secure and reliable connection point that allows for easier maintenance and troubleshooting. They can also help in organizing wiring, reducing the risk of accidental shorts or disconnections.

In contexts where the question posits that the action must be avoided, it could be due to a scenario where the terminal block is improperly rated, poorly secured, or not suitable for the specific application, which could lead to problems. However, in general practice, avoiding going through a terminal block is not typical guidance; rather, it is frequently recommended to enhance safety and functionality.

The other options present valid concerns: using a wire of insufficient gauge can lead to overheating or voltage drop, using non-insulated wiring poses significant safety hazards by increasing the risk of short circuits or electrical shock, and connecting directly to output devices can bypass necessary safety controls or fuses. Each of these actions could potentially create unsafe conditions or operational issues that complicate the electrical system's effectiveness and reliability.