SHAFT 8S0490 - Caterpillar

Grounding Practices
The connection of battery cables to a battery and the disconnection of battery cables from a battery may cause an explosion which may result in injury or death. The connection and the disconnection of other electrical equipment may also cause an explosion which may result in injury or death. The procedures for the connection and the disconnection of battery cables and other electrical equipment should only be performed in a nonexplosive atmosphere.
Proper grounding for the auxiliary equipment and engine electrical systems is necessary for proper performance and reliability. Improper grounding will result in uncontrolled electrical circuit paths and unreliable electrical circuit paths.Uncontrolled engine electrical circuit paths can result in damage to main bearings, crankshaft bearing journal surfaces, and aluminum components. To ensure proper functioning of the equipment and engine electrical systems, an engine-to-frame ground strap with a direct path to the negative battery post must be used. This may be provided by way of a starting motor ground, a frame to starting motor ground, or a direct frame to engine ground. An engine-to-frame ground strap must be used in order to connect the grounding stud of the engine to the frame of the vehicle and to the negative battery post.
Illustration 1 g01117393
Grounding stud to -Battery ground
Illustration 2 g01117394
Alternate grounding stud to -Battery groundThe engine must have a wire ground to the battery. Ground wires or ground straps should be combined at ground studs that are only for ground use. All of the grounds should be tight and free of corrosion.All of the ground paths must be capable of carrying any likely current faults. An AWG #0 or larger wire is recommended for the grounding strap to the cylinder head.
When boost starting an engine, the instructions in Operation and Maintenance Manual, "Engine Starting" should be followed in order to properly start the engine.This engine may be equipped with a 12 volt starting system or a 24 volt starting system. Only equal voltage for boost starting should be used. The use of a higher voltage will damage the electrical system.The Electronic Control Module (ECM) must be disconnected at the "J1/P1" and "J2/P2" locations before welding on or near the engine.
The engine has several input components which are electronic. These components require an operating voltage. Unlike many electronic systems of the past, this engine is tolerant to common external sources of electrical noise. Buzzers that use electrical energy can cause disruptions in the power supply. If buzzers are used anywhere near the engine, the engine electronics should be powered directly from the battery system through a dedicated relay. The engine electronics should not be powered through a common power bus with other key switch activated devices.