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Subject: Zincs corrosian 2 Author: JD [ Next Thread | Previous Thread | Next Message | Previous Message ] Date Posted: 7:37pm LAST EDITED ON Feb-21-04 AT 08:19 PM (PST) Problems..... I wasn't suggesting that Wideopen has those problems, I was just trying to explain why some say to include the engine in the zinc system, and some say to exclude it. The Problem of electrons jumping ship is extremely rare but a real danger. There have been documented instances where boats sank at slip because a dock ground leached out the zincs then and ate holes in aluminum hulls. Isolators are primarly sold for commercial metal boats but are a good idea for anyone with a large boat that has both AC a DC electronics aboard. These are tools of prevention not cures. Insurence!! If your AC case grounded toaster is sitting against your grounded aluminum hull, causing drastic Galvanic corrosian, it's probably more prudent to move the toaster, then shop for an Isolater. Still if you have an isolator it will save your butt if you put the toaster in the wrong place Single strand!!!! Man I wish I'd thought of it before I wired my boat. Almost all the problems I've seen in boat wiring were do to multistrand leaching up saltwater and coroding internally in the wire. I know the theory. Under load electrons move to the edge of the wire avoiding the core. Multiple strands mean more edges to carry the current so they conduct better under heavy load. In Welding this is really apparent: welding leads are extreemely fine wire having hundreds of strands. Somewhere along the line some engineer thought stranded is better so it must be better for marine as well. I'm begining to think that's BS Unfortunately they forgot about the wires whicking ability and the fact that more edges exposed to saltwater means greater: more rapid corrosian and a much faster reduction in capacity. This is all just one of my crazy theories but I think I'm on to something. Say you took 12 guage wires: single and multi strand and ran it to two bilge pumps in a wet bilge. Even if you sealed the wires to the best of your ability they'd both would show corrosian in the first year. This is just a guess but say 50% of the multistrand wire is surface mass exposed to corrosian, in contrast maybe 10% of the single strand wire is surface edge mass. If both oxidise equally the solid wire looses 10% of its capacity, the multistrand 50% of it's capacity. In the multi the corrosian would run right through it to the core, causing heavy resistance throughout the wire. In contrast in single strand only the outer edge of the wire would be oxidised and the inside core clean. The current would still have a clean low resistance path in the core of the wire. Say in ten years that solid wire oxidised to half is original diameter. It still would be more then 18 guage, more then enough to run the pump, with a clean copper path to run the voltage. I'd say in equal condidtions the multistrand would inevitably fail first. If I was wiring a boat tomarrow. I'd probalbly run all single strand except for high draw applications. It's my understanding that the resistance advantage of multistrand only makes a difference when the wire is maxing out on it's current capacity. Battery cables, anchor winchs etc shouuld be stranded but for small things like pumps I'd run single strand. I know it's not code but I've been thinking alot about it and I think it's the way to go. The next skiff I build will definately lean that direction. I gather your in the wiring business, not me...LOL I just like doing things myself. The great thing about doing things for "fun" or yourself is you don't have to worry if someone says you did it wrong and hires ten "experts" and a lawyer Good stuff...fun to post about, but I've got to get back to welding some bronze. Tight lines, Jim [ Next Thread | Previous Thread | Next Message | Previous Message ]