http://www.sparkyuonline.com In this video I am describing how a 3 phase panel is built and how the bussing works in accordance w/3 phase power. It is part of electrical wiring systems common in the U.S.. This electrical panel is a 3 phase 4 wire 120/208 v 200 amp panel with 42 spaces. It is considered a bolt on breaker style with a main circuit breaker.