Damaged or severely corroded conductors
Slide 1 of 2: Well before collapses
Slide 1 of 2: Well after collapses
Slide 2 of 2: Close up. Well before collapses. The problem was poor quality grout at top of conductor which allowed hidden but active corrosion on the next casing.
Slide 2 of 2: Well after collapses. The corroded casing has collapsed on itself creating a need for major repair.
Conductor failed at waterline due to long term corrosion