technical article from Blue Sea Systems
The 600 Ampere busbar from Blue Sea Systems, PN 2104, is useful as a negative tie point. It has a continuous amperage rating of 600A DC. In addition to the four large stud terminals for high current carrying large wire terminals, it has four screw terminals (two on each end) for low-current, small-wire connections.
In boats with two or more engines and two or more battery banks, use the 600A busbar to tie together engine blocks and battery bank negative terminals. According to American Boat and Yacht Council (ABYC) rules: 18.104.22.168. "Multiple Engine Installation - If a boat has more than one engine with a grounded cranking motor, which includes auxiliary generator engine(s), the engines shall be connected to each other by a common conductor that can carry the cranking motor current of each of the grounded cranking motor circuits."
Original article from Blue Sea Systems