If you're using strippers that have sharp blades on them (little
notches that fit your wire sizes perhaps), you are cutting not only the coating
of the wire but the wire too. This means you have penetrated ever so slightly
the wire that over time can fatigue at that cut and eventually break or
decrease the carrying capacity or both. Look at your wire and see if there isn’t
a nick where the coating was stripped. That’s where it breaks. A thermal
wire stripper is a good way to prevent these problems:
Downside? High cost … $300 or thereabouts. Ebay has ‘em for
way less.
Jim