The story
Referencing the fact that when one end is plugged into a live outlet, the exposed prongs of the other end are highly dangerous.
Etymology from Wiktionary, CC BY-SA 4.0.
suicide cable
Today it means: A simple electrical cord with prongs on both ends; plugging one end into a live outlet (for example a generator) and the other end into a dead outlet (in a house with no power) allows power to be injected from the live outlet into the dead one. Full definition →