"Landing Gear Alternate Extension
The alternate landing gear extension system uses a dedicated DC powered electric hydraulic pump. Fluid within the supply line to the pump is sufficient for alternate gear extension operation. This fluid is isolated from the left hydraulic system. Selecting the ALTN GEAR EXTEND switch releases all door and gear uplocks. The landing gear free–fall to the down and locked position."
ref -
http://navfly.ru/wp-content/uploads/...ons_manual.pdf
I have not found any reference to an associated circuit breaker.