Beech 1900
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Executed Go Around / Missed Approach; General Declared Emergency; General Maintenance Action
Aircraft; Procedure
Upon selecting gear down the Landing Gear Relay CB popped immediately.  I was PF and we went around and were still talking to Approach; so we told them we were going to go to the VOR to hold as published to run our checklists.  I spoke with the passenger and then contacted operations to declare our emergency and get them in touch with Dispatch and Maintenance Control.  We also declared an emergency with Approach.  I gave controls to the First Officer and then performed the Failure of Landing Gear to Extend Normally Checklist.  After running the checklist the gear was determined unsafe.  We then ran the Landing Gear Manual Extension Checklist and the gear was extended.  We got all three green and all tests contained in the checklist passed.  After conferring with dispatch and mx control we deemed the gear safe and were all comfortable with taxiing the plane to the terminal.  After all checklists were completed; I took control of the airplane again and commenced landing.  We landed without incident.  We stopped on the runway and had ARFF take a look to see if anything looked out of the ordinary; they said no so we continued to the terminal.  During the whole process our pax were kept abreast of the status of our flight and were told to expect a normal landing.  This is the third time today that a company aircraft has had gear issues.  This is the second time in less than a month that the landing gear wouldn't extend normally for me personally.  Something is wrong with this picture.  I don't know how to fix this; but someone should probably figure it out.
BE1900 Captain reports the landing gear relay circuit breaker tripping as the landing gear is selected down.  A go-around is initiated and the landing gear is extended manually.  A safe landing ensues; but the reporter states that landing gear malfunctions are a common occurrence at his company.