Lightning Protection Systems
The lightning protection system (LPS) comprises a number of components that work together to help to prevent damage caused by a lightning strike;
The lightning conductor – A lightning conductor should be installed at the masthead. This should be a turned copper spike of at least 12mm (1/2”) in diameter, or a hemispherical dome tipped spike, and project at least 150mm (6”) above the highest point.
The down conductor – Lightning conductors should be of at least 100mm2 (4AWG) cross sectional area.
Terminations. The lightning conductor should be terminated at the hull, keel or an immersed ground plate with a minimum area of .02 m2 (2 ft2) (Payne, 2007)All terminations and connections should be crimped and soldered joints should not be used. Never use soldered joints alone, as they may overheat and melt during a strike causing further havoc, it is very difficult on large cables to ensure a good low resistance solder joint. After crimping, soldering can be run in to enhance the joint, however this is not really necessary. Always crimp the connections and ensure that all bonded connections are clean and tight. All connections should be bolted to the ground point.A bridge or link should be installed between the ground plate bolts or at least two keel bolts to distribute strike current. It is recommended that you bridge out the two bolts with a stainless steel link to spread the contact area and therefore the current carrying capacity. Links can also be drilled and used to bolt the ground cable connector, as many ground shoes have relatively small bolts designed for RF grounds only.
Earthing of the electrical systems on watercraft is important for the safety of all on board and those nearby, such as on occasions when the craft is moored. Electrical safety is a requirement of the Recreational Craft Directive and is covered in the British Marine Electronics Association “Code of Practice”.
For more information on grounding systems in watercraft, we recommend the book “The Boatowners Electrical and Mechanical Manual” by Nigel Calder (a world renowned expert), published by Adlard Coles Nautical in 2005..
Corrosion Protection Systems
All watercraft, particularly those in a salt-water environment, are subject to corrosion. One method of overcoming the effects of corrosion is to use a sacrificial anode. The anode protects components which cannot be easily replaced, but it must be in electrical contact with the components to be protected.
We produce cables that allow you to simplify the grounding and cathodic protection wiring, using corrosion resistant materials and construction.
For further advice and information about sailing and thunderstorms: http://www.sailnet.com/forums/cruising-articles/20341-lightning-strike.html