See my post #49 above. I've also had issues with customers wiring harnesses where it flexes and breaks the conductor inside but believes the outer insulation. I put about 5 pounds of stretching force on each individual wires, especially near the connectors. If it stretches the conductor inside is faulty. Regarding grounds they can look good but don't pass the high amperage needed. Voltage drop is the way to test them, but unbolting them and cleaning them with a wire brush, and putting dielectric grease on the connection is good preventative maintenance anyway.