We claim the ornamental design for an insulator pin for overhead electrical lines, as shown and described.
FIG. 1 is a top perspective view of an insulator pin for overhead electrical lines, showing our new design;
FIG. 2 is a front elevation view thereof, the back elevation view is identical to the front elevation view;
FIG. 3 is a right side elevation view thereof, the left side elevation view is identical to the right side elevation view;
FIG. 4 is a top plan view thereof; and,
FIG. 5 is a bottom plan view thereof.
The dashed lines depict portions of the invention that form no part of the claimed design. The wavy line broken away symbols in the drawings indicate the appearance of any portion of the insulator pin for overhead electrical lines between the wavy lines forms no part of the claimed design.