Fail Safe Insulator Bases

Lindsey Fail-Saf insulator bases are designed to fail safe at overloads predictably below the rated insulator strength. This permits the base to plastically deform and yield in to the load without fracture, avoiding damage to the insulator and the associated cascading effect, holding he conductor above ground for easy repair.
http://lindsey-usa.com/hardware/pole-line-hardware-insulating-bases/
The reliability and ultimate performance of horizontal line post insulators mounted on rigid structures is limited by the insulators ability to withstand severe loading conditions, such as a broken conductor, galloping, heavy ice loading or other highly unbalanced longitudinal loads. It is well known that when horizontal line post insulators are mounted on flexible structures, their ability to withstand severe longitudinal loading is greatly enhanced.
http://lindsey-usa.com/wp-content/uploads/2015/10/04C-001-FAIL-SAFE-BASES-10-20151.pdf
The Lindsey Fail-Safe Base improves the integrity of horizontal line post construction by providing a flexible support for the insulator. This flexibility lowers the dynamic stresses induced in an insulator by an impact load. In addition to this elastic flexibility, Fail- Safe Bases are designed to plastically deform at a predetermined level, thus limiting the maximum cantilever load that can be applied to the insulator. These features protect the insulator not only from longitudinal overloads but also from vertical overloading, e.g. from severe ice conditions.