Floscan Pre-Installation Manual for Diesel Models - Manual (Page 11)

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Bonding
Electrically connecting the vessels' engines and metal objects with Copper strap will produce an adequate ground. It’s not
necessary that the ground actually be in contact with the water. We want as large a conducting mass as possible. This is
achieved through extensive bonding, or connecting everything together. In twin engine vessels connect both engines. Connect
them to the generator, hydraulic system, fuel tanks, reduction gear, propulsion shafting via shaft brushes, and water tanks.
Anything that is metal and has some mass should be connected.
• Don’t bond to any through-hull fittings. Their mass is small and connecting to them may cause Galvanic Corrosion
elsewhere.
If the vessels other electronics are performing poorly, or suffering noise-related problems, a 4-inch to 6- inch wide, 26 gauge
or thicker copper strip should be installed. Run the copper strip fore and aft along the inside of the hull, at or below the water
line. Compared to Copper, seawater is a relatively poor conductor. This means that we need to contact the water over a large
and spread-out area. A narrow strip 1inch wide by 10 feet long will work far better than a 12 inch by 12-inch sheet, even
though it has less surface area. The actual area is less important than extending the strip as far forward and aft as possible.
Bond the strip directly to the engines, reduction gears, propulsion shaft brushes, and everything else. The advantage of
bonding to a copper strip is that it allows you to make short, direct connections, and increases the, “Ground’s” efficiency.
Skin Effect
AC noise and static are, “Broadcast” in the Radio Frequency, (RF) Spectrum. Current flowing through copper conductors at
these frequencies tend to crowd towards the conductors outer surface. This is known as, “Skin Effect” and effectively
increases the conductors’ resistance to current flow. The actual current carrying depth of a conductor is only about .0015
inch, because of skin effect.
Use 2 to 3 inch wide copper strap when making bonding connections. Round conductors are inefficient due to their minimal
surface area, and won’t work nearly as well as flat strap.
Shielding
Wiring between FloScans’ Sensors, Tachometer Senders, and Instruments must be with shielded cable. Each pair of Sensors
and each Tachometer Sender must have its own dedicated shielded cable. The shields, through their drain lines must be
connected directly to ground in the engine room, and not
through a ground buss. Make all connections short and
direct.
Ground
For our discussion the, “Electron Superhighway Interface” between vessel and Earth is, “Ground”. Ground can be a:
• Ground Plate.
• Conducting Mass.
• Combination of Both.
It isn’t:
• The Battery’s Negative Terminal.
• The Negative Battery Buss.
• Wiring connected to the Battery’s Negative Terminal or Battery Buss.
Connections to ground should be short and direct. The negative terminal and battery buss should be connected to ground, but
ground connections shouldn’t be made through them.