HOOD & GUARD GP 5270155 - Caterpillar

The installation requires an Unswitched +Battery connection. This connection is made to the Customer Connector P3, pin-1. The connection can be made at any unswitched battery connection in the vessel. Current draw for this circuit is 6 mA at 12 VDC (or 24 VDC) when the ECM is not powered up.Circuit protection for the Unswitched +Battery connection is specified as 5 Amp (1 Amp minimum).This line does not require dedicated circuit protection, however it is recommended.
Figure 1.2 Unswitched +Battery ConnectionBattery Disconnect Switches
To avoid loss of trip data stored by the ECM via the Unswitched +Battery line, disconnect switches should not interrupt either the ECM -Battery or Unswitched +Battery lines. The ECM and monitoring display MUST be powered from the same switch (source). The same battery source must be used for all positive battery and negative battery connections.Vessels may be equipped with an engine protection shutdown system (external to ECM) that interrupts electrical power to the ECM. These systems will not supply power to the ECM until the engine is cranked, until oil pressure achieves minimum acceptable limits or until the engine shutdown verify override button is depressed.These devices must not interrupt the unswitched positive battery line. Current draw from the ECM through the Unswitched +Battery line is less than 10 mAmps (0.01 Amps) and will not cause a battery to discharge unless the engines are unused for an extended period of time (i.e. months).Welding on a Vessel Equipped with an Electronic Engine
Before welding on a vessel equipped with an electronic engine, the following precautions should be observed:1) Disconnect all cables connected to the vessel batteries.2) Disconnect both ECM Connectors (J1/P1 and J2/P2).3) Do not use the ECM or Engine Ground Stud for grounding of the welder.4) Locate the welding ground as close as possible to the welding area.