Grounding to keel bolt help
- Thread starter tahoemark
- Start date
Lightning protection is a whole kettle of controversial fish. The best lightning protection is a good insurance policy that will pay for everything once you get hit.
Unfortunately I can't remember a good source, other than a guy on the Sabre email list. Harry's take on it is that a lightning strike sends a large current through the mast and out anyway it can get to ground. This requires a very heavy wire, say 2/0 or larger led from the mast step in a straight a line as possible to a keel bolt. Bends in the wire will increase the chance of the energy arcing and taking a shortcut to ground, which could be by way of a through hull or straight through the fiberglass.
Grounding deck step masts are more difficult because it is difficult to get a straight run to a keel bolt and the wire may be 7 or more feet long. Keel stepped masts are easier because they are obviously closer to the keel.
The guiding thought in this, is that electricity is fundamentally lazy, it will take the shortest easiest route to get where it wants to go. Lightning wants to get from the cloud to the earth, if it is easier to go through your mast, it will. Once in the mast, it will get to the water anyway it can, big wires, short cable runs offer the best chance of reducing damage.
Unfortunately I can't remember a good source, other than a guy on the Sabre email list. Harry's take on it is that a lightning strike sends a large current through the mast and out anyway it can get to ground. This requires a very heavy wire, say 2/0 or larger led from the mast step in a straight a line as possible to a keel bolt. Bends in the wire will increase the chance of the energy arcing and taking a shortcut to ground, which could be by way of a through hull or straight through the fiberglass.
Grounding deck step masts are more difficult because it is difficult to get a straight run to a keel bolt and the wire may be 7 or more feet long. Keel stepped masts are easier because they are obviously closer to the keel.
The guiding thought in this, is that electricity is fundamentally lazy, it will take the shortest easiest route to get where it wants to go. Lightning wants to get from the cloud to the earth, if it is easier to go through your mast, it will. Once in the mast, it will get to the water anyway it can, big wires, short cable runs offer the best chance of reducing damage.