solid door will allow the full 300 ampere capacity of the cutout to be utilized. Cutouts are typically mounted about 20 degrees off vertical so that the center of gravity of the fuse holder is displaced and the fuse holder will rotate and fall open under its own weight when the fuse blows. Mechanical tension on the fuse link normally holds an ejector spring in a stable position. When the fuse blows, the released spring pulls the stub of the fuse link out of the fuse holder tube to reduce surge duration and damage to the transformer and fuse holder. This quenches any arc in the fuse holder. Each fuse holder typically has an attached pull ring that can be engaged by a hook at the end of a fiberglass hot stick operated by a lineworker standing on the ground or from a bucket truck, to manually open the switch. While often used for switching, the standard cutout shown is not designed to be manually opened under load. For applications where the switch is likely to be used to interrupt power manually, a "load break" version is available that has an attachment to quench the arc. Standards Up until the mid-1990s each manufacturer used their own dimensional standards for cutout design; by the late 1990s most cutouts were of an "interchangeable design". This design allows for the interchangeable use of cutout bodies and fuse holders manufactured by different vendors. External links Patent 1,939,371 — 1930 cutout with single hinge Patent 2,176,227 — 1932 cutout with double hinge Patent 2,519,289 — 1944 cutout with lightning arrestor inside the insulator Patent 6,583,708B1 — recent cutout design Electric power systems components Electric power distribution Safety switches