GLASS 4553948 - Caterpillar

Grounding Practices
Properly ground the electrical system for the vessel and the engine. Proper grounding is necessary for optimum engine performance and reliability. Improper grounding will result in uncontrolled or unreliable electrical circuit paths.Uncontrolled or unreliable electrical circuit paths may result in damage to main bearings, crankshaft bearing journal surfaces, and aluminum components. Uncontrolled electrical circuit paths may also cause electrical noise. Electrical noise may degrade the performance of the vessel and of the radio.Connect the starting motor directly to the negative battery terminal. Connect the alternator to the negative battery or negative terminal for the starting motor. The alternator and the starting motor must meet marine isolation requirements.Note: All electrical connections must meet or exceed the American Boat and Yacht Council Standard E-11 or your local Marine Classification Society.Use a bus bar with a direct path to the negative battery terminal for low current components that require a negative battery connection. Connect the bus bar directly to the negative battery terminal.Note: All return paths to the negative battery must be able to carry any likely fault currents.The use of a bus bar ensures that the electronic control module (ECM) and the components connected to the ECM have a common reference point.Refer to Special Instruction, REHS1187, "Marine Engine Electronic Installation Guide" for additional information on grounding procedures.Negative Battery Connection for Multiple Engines
Illustration 1 g03668717
(1) Vessel grounding bus bar
(2) Alternating current (AC) grounding bus bar
(3) Engine negative terminal
(4) Engine
(5) Starter
(6) Battery disconnect switch
(7) Battery Note: Illustration 1 is applicable for wood and fiberglass hulls only.Note: The engine negative terminal (3) must be a clean, metal to metal contact.Install the battery disconnect switches as close as possible to the battery positive (+) but outside of the battery enclosure.Note: If multiple bus bars are used to connect components to the negative battery, a common reference should be provided. All bus bars must be wired together for proper engine synchronization for multiple engine operations.