Grounding — optional dedicated drain wire

Frequencies emitted from equipment such as switched mode power supplies or MF/HF transmitters can cause interference with your displays’s touchscreen or power swipe. If you experience issues with touchscreen performance or the power swipe, fitting an additional dedicated drain wire can resolve the issue.
Important

The additional wire is required in addition to the drain wire (shield) that is part of the product’s power cable, but should ONLY be used when touchscreen or power swipe interference is observed.

Dedicated grounding

Connect one end of the additional drain wire (not supplied) to your product using the supplied crimp, washer and screw.

Connect the other end of the additional drain wire to the same point as the power cable drain wire (shield). This will be either the vessel's RF ground point, or on vessels without an RF ground system, the negative battery terminal.

The dc power system should be either:

  • Negative grounded, with the negative battery terminal connected to the vessel's ground; or

  • Floating, with neither battery terminal connected to the vessel's ground.

If several items require grounding, they may first be connected to a single local point (e.g. within a switch panel), with this point connected via a single, appropriately-rated conductor, to the vessel’s common RF ground point.

Implementation

The preferred minimum requirement for the path to ground is via a flat tinned copper braid, with a 30 A rating (1/4 inch) or greater. If this is not possible, an equivalent stranded wire conductor may be used, rated as follows:

  • for runs of <1 m (3 ft), use 6 mm2 (#10 AWG) or greater.

  • for runs of >1 m (3 ft), use 8 mm2 (#8 AWG) or greater.

In any grounding system, always keep the length of connecting braid or wires as short as possible.

References

  • ISO10133/13297

  • BMEA code of practice

  • NMEA 0400