How much insulation you take off is a specification, not a judgement call. Too little and the insulation is in the connection; too much and bare conductor is sticking out of it.
Both errors look like a finished termination. One puts insulation where metal should be touching metal; the other leaves live copper exposed outside the device that was supposed to contain it.
There is a window, and both edges of it matter. Strip short and insulation ends up inside the clamp, so part of what should be a metal-to-metal connection is plastic. Strip long and conductor extends past the device. The manufacturer publishes the length because the device was designed and tested around it.
Check yourself: Is a longer strip a safer bet, since at least the insulation is definitely out of the way?
Answer: No. More bare copper is not automatically a better connection.
The device permits a specific amount of exposed conductor. Going past that leaves live metal outside the part that was built to enclose it, which is a different failure from the one you were avoiding, not an improvement.
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Written from the owner's poster for this lesson. Nothing added beyond what the poster states.
Written for Texas apprentices as free study material. The Texas apprentice licence is an application, not an exam (Occupations Code 1305.161), and nothing here counts as apprenticeship hours or continuing-education credit. VoltMark is not affiliated with, endorsed by, or sponsored by NFPA, PSI, TDLR, or any state or local licensing authority. Always follow your employer's safety programme and your supervising electrician.
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