Выражение встречается в следующем контексте:

Elevator: Electrical requirements.
Risers fuses - 3x25A

Заранее спасибо

**A riser card is a printed circuit board that picks up a multitude of signal lines (often bussed) via a single connector (usually an edge connector) on a main board and distributes them via dedicated connectors on the card.
Riser cards are often used to allow adding expansion cards to a system enclosed in a low-profile case where the height of the case doesn't allow for a perpendicular placement of the full-height expansion card.
A riser card is a board that plugs in to the system board and provides additional slots for adapter cards. Because it rises above the system board, it enables you to connect additional adapters to the system in an orientation that is parallel to the system board and save space within the system case.**
http://en.wikipedia.org/wiki/Riser_card