If copper is removed when stripping a wire, the correct action is to:

When stripping a wire, if copper is removed, it indicates that too much insulation or material has been taken off the wire, potentially compromising the integrity of the electrical connection. The best course of action in this scenario is to cut off the damaged portion and start over again. This ensures a clean connection, providing reliable conductivity without the risk of short circuits or other electrical issues caused by improper stripping.

Using a crimp connector might be a solution in specific situations, but it is not ideal as it wouldn't address the underlying problem of having compromised wire integrity. Additionally, calling a supervisor may not be necessary unless company policy dictates so; however, in the context of the question, it is more prudent to resolve the issue independently. Continuing the work with a damaged wire could lead to failures or hazards later on, making it an unsafe option.