Fuse Cutout

https://www.hbygle.com/products/fuse-cutout-switch-electrical.html

Fuse cutouts, also called cut-out fuses, are used in primary overhead feeder lines and taps to safeguard distribution transformers against overloads and current surges. They function as a combination of a fuse and a switch. The transformer will be disconnected from the line when the fuse melts due to an overcurrent brought on by a defect in the transformer or customer circuit. Utility linemen standing on the ground and using a long insulating stick known as a "hot stick" can manually open it as well.