A BFC is shop slang for an unusually large and heavy-duty capacitor, typically a high-voltage film or electrolytic type. These components are built to handle massive energy dumps, high ripple currents, and electrical arcs in systems like motor starters, power transmission lines, or large power supplies. Technicians use the term to emphasize the physical bulk and potentially lethal stored energy of the component.
Heard on the job
Make sure you bleed that BFC before reaching into the chassis, or it will throw you across the room.
Insider tip
Always assume a BFC is fully charged and verify it with a meter before touching the terminals.