Installing a Rear Camera on the CAT 345B: Power Access and Practical Solutions

[MikePhua]

Understanding the CAT 345B Electrical System
The Caterpillar 345B excavator operates on a 24V electrical system, typical of heavy-duty machinery. This system powers essential components such as the engine control module (ECM), lighting, and auxiliary systems. When adding aftermarket accessories like a rear camera, sourcing switched power—power that activates only when the ignition is on—is crucial to avoid draining the batteries.
Terminology Notes

• Switched Power: Electrical power that is only available when the ignition key is turned on.
  
• Main Power Relay: A relay that controls the distribution of power to various systems in the machine.
  
• Buss Bar: A conductive bar used to distribute power to multiple circuits.
  
• 24V to 12V Converter: A device that steps down voltage for accessories requiring 12V input.
  
• Fuse Tap: A connector that allows safe access to power from an existing fuse slot.
  
• Purple Wire: In this context, a large-gauge wire carrying switched 24V power from the relay.
  

Field Solution: Tapping into Switched Power
To install a rear camera without running a cable all the way to the cab, technicians identified a practical solution: tapping into the purple wire at the main power relay located near the rear of the machine. This wire provides 24V when the key is turned on, making it ideal for accessories that should only operate during machine use.

• Use a fuse near the tap point to protect the camera circuit.
  
• If the camera requires 12V, install a 24V to 12V converter inline.
  
• Alternatively, connect to the existing converter in the cab that powers the radio and outlet.
  

Installation Tips and Safety Considerations

• Always verify voltage with a multimeter before tapping.
  
• Use weatherproof connectors and secure wiring to prevent vibration damage.
  
• Label new wiring for future maintenance clarity.
  
• Avoid tapping into circuits that power critical systems like ECM or sensors.
  

Anecdotes from the Field
In Arizona, a contractor retrofitted a fleet of CAT 345Bs with rear cameras to improve safety during night operations. Initially, they routed power from the cab, but after discovering the purple wire at the rear relay, installation time dropped by 40%. The change also reduced cable clutter and improved reliability.
In a separate case in British Columbia, a technician installed a camera using an unprotected tap from the lighting circuit. A short circuit during a rainstorm disabled the machine’s lights and triggered a fault code. The lesson: always fuse accessory circuits and avoid piggybacking on critical systems.
Broader Industry Context
Rear cameras have become standard on newer excavators due to rising safety standards. In 2024, a construction firm in Ohio reported a 30% reduction in backing incidents after retrofitting older machines with cameras and proximity sensors. Manufacturers now offer factory-installed systems, but retrofits remain common for legacy fleets.
Conclusion: Smart Wiring for Smarter Machines
Installing a rear camera on a CAT 345B is more than a convenience—it’s a safety upgrade. By tapping into switched power at the rear relay and using proper voltage conversion and protection, operators can enhance visibility without compromising the machine’s electrical integrity. As one technician put it, “A good camera install is invisible until you need it—and then it’s indispensable.”