Marine Devices with a Chassis Ground Screw

Many Garmin® marine devices have a chassis ground screw to help prevent electrical interference. A marine-grade copper solid or stranded wire should be connected at the chassis ground and taken to the water ground. Examples of “water ground” could be found in different circuitry, wires, and connections to different systems of the vessel.  Refer to the vessel's electrical distribution system to identify them or contact the vessel manufacturer. 1   Highly recommended for touchscreen devices. The chassis ground screw should not be connected to the to the voltage ground.

Bonding a marine device (chartplotters, sounder modules, e.g.) using the device's chassis ground provides some protection to the internal circuits and components from directly induced electrical currents. 

NOTE: Bonding a marine device using the chassis grounding point may not stop or prevent damage caused by a lightning strike.

If a screw is needing to be replaced, below is a list of the screw sizes and corresponding units for each type and size of screw:

M3x0.5x4.0,PHP,SS/P,Nylon

• echoMAP™ 7x chartplotters

• ECHOMAP™ Ultra chartplotters

• ECHOMAP™ Ultra2 chartplotters

• GPSMAP® 7x1 chartplotters 

• GPSMAP® 7x2 chartplotters | GPSMAP® 9x2 (Plus) chartplotters

• GPSMAP® 7x3 chartplotters | GPSMAP® 9x3 chartplotters | GPSMAP® 12x3 chartplotters

• GPSMAP® 10x2 chartplotters | GPSMAP® 12x2 series (Plus) chartplotters

• GPSMAP® 74xx series chartplotters |GPSMAP® 76xx chartplotters

• GPSMAP® 84xx chartplotters | GPSMAP® 86xx chartplotters
  

• GPSMAP 16X3

M3x0.5x6.0,PHP,SS/P,Nylon

• GMM™ 150 monitor | GMM™ 170 monitor | GMM™ 190 monitor

• GPSMAP® 8xxx chartplotters

• GPSMAP® 8500 black box | GPSMAP® 8530 black box
  
  

M4x0.7x5,PHP/S,SS/P

• STRIKER™ 7 fishfinders| STRIKER™ 9 fishfinders

• STRIKER™ Plus 7 fishfinders | STRIKER™ Plus 9 fishfinders

• STRIKER™ Vivid 7sv fishfinders | STRIKER™ Vivid 9sv fishfinders
  
  

M3x0.5x8.0,PHP LW/W

• Garmin AIS™ 600 transceiver

• VHF 100

• VHF 200

• VHF 300

• VHF 300 Garmin AIS™

• GPSMAP® 90xx chartplotters

• GPSMAP® 92xx chartplotters
  

• GSD™ 28 sonar module

M3x0.5x10.0,PHP,SS/P,Nylon

• GSD™ 24 sonar module

• GSD™ 26 sonar module
  
  

M4x0.7x6,PHP,SS/P,w/Nylon

• GMR™ 424 xHD2 radar | GMR™ 426 xHD2 radar

• GMR™ 624 xHD2 radar | GMR™  626 xHD2 radar

• GMR™ 1224 xHD2 radar | GMR™ 1226 xHD2 radar

• GMR™ 2524 xHD2 radar | GMR™ 2526 xHD2 radar
  
  

M4x0.7x8,PHP,SS/P,w/Nylon

• GMR Fantom™ pedestals
  
  

Terminal Ring, 18-14 AWG  #6 Solid or Stranded Copper Wire Panduit-2176

• GLS™ 10 sonar module

¹ On a marine vessel, the DC ground or electrical bond may also be referred to as a "water ground". Refer to the vessel's electrical distribution system to identify them.