What kind of wire should never be exposed when making connections?

Uninsulated wire should never be exposed when making connections because it poses a significant safety hazard. When wires are uninsulated, the conductive metal is exposed and can easily come into contact with other conductive materials, creating a risk of short circuits or electrical shocks. This lack of insulation increases the likelihood of electrical faults that can result in fires, equipment damage, or personal injury.

In contrast, insulated wire is designed with a protective coating that prevents accidental contact with other conductive surfaces and reduces the risk of electrical interference. Stranded wire consists of multiple small wires bundled together, and while it may have insulation, it is fundamentally safe when properly insulated. Sheathed wire features a protective outer layer that further safeguards against mechanical damage and moisture exposure. Therefore, only uninsulated wire is deemed unacceptable for safe electrical connections.