How to find straycurrents in alternator, solar panels and wind turbine

[skenn_ie]

All those systems should be fully isolated until their wires connect to the main positive and negative terminals.

[Capn Jimbo]

Oh my…


This whole madhouse of commentary based on the single notion that the problem simply MUST be electrical, and why? Because “a rigger with a good reputation” said so? And evidenced by rust? And that occurred on rigging unconnected to the electrical system? And that also occurs at the top of a shroud? And evidenced by a few broken strands? And with swaged connectors? And on rigging less than a year old?


Really? I was at a good yard, good reputation in a good sailing state, Florida, maybe 150 boats. And who referred me to two riggers with “great reputations”. Because I spec’d my own materials (including Sta-loks) I didn’t worry about the materials – but neither seemed to notice the boat was on the hard, and that the mast rake was unclear and needed to be determined. Nope, they’d just replace the rigging – one wanted to pull the mast (good, check everything), and the other well, he’d just send his monkey up and simply change the rigging as it already was. Neither noticed undersized pins on the stays and shrouds. Both eyeballed the mast angle and said it was “fine”!


Great reputations, though.


Let’s start at the beginning, shall we? Sure. The OP has as yet not posted a single good close-up picture of the problem. If his very young rigging is like the example he linked from another boat, it is terribly and completed rusted (looked like 20+ years old, or more). Further we are not told any of the details of the install – cost, type of stainless, rigger details and the like.


A jump to the “stray current” lily pad on this basis is hardly justified.



Although his meter readings are rough, they didn’t change even when the negative cable was removed. So back to the beginning again. I truly wish we had the now essential pictures of the issue, but assuming the OP’s example pic is accurate, this is a case of HEAVY, thick red brown rust, the kind that can only occur from extreme age (not true here, very young rigging) – or – it isn’t 316 SS. At such a young age, I would expect any literal rust to be very minor, and concentrated where the cable enters the swage – you’d have to look closely.


Let’s keep in mind that SS tends to pit, or in extreme cases to crevice. Again, a pic please? A typical pit is well, a pit that may have a bit of rust, yes, in the pit. Crevices if extreme would be visible. If minor, or cracking a blue dye test would be required to even find them.


To me the issue is pretty clear, at least at this stage. I don’t believe this is good quality 316 SS. It would not be beyond possibility that the unknown rigger used 304 and/or even a low quality 304. It is well known that 304 SS should NEVER be used in a saltwater environment, as it will rust, and more visibly. And the amount of rust in such a short time as the OP is suggesting, suggests to me really poor wire.


The fact that we have had several isolated breaks of strands – top and bottom – would imply low quality or poor swaging – if the swages are too compressed the strands may be weakened. I find it hard to believe that stray currents would so quickly work through just a few of the 1x19 strands without bothering the others in the area. Further consider the location of the breaks – at the swages.


Think about it. I’ll bet my cajones that we have a combination of poor materials AND poor workmanship. And I ask the OP – what prevents you from having the original rigger to remake and send you the rigging, as (if he/she is competent) should have exact measurements of the job?


Couple recommendations:


1. Call the unnamed rigger and talk to him about the problem. The OP states he normally would have asked for a redo, except that he’s not in the area any longer. But I’d definitely like to hear that rigger’s take. Ask him specifically what kind of SS wire he used, manufacturer, supplier and how long he’s been using it. How long was the guy in business? Any recommendations?


Swaging machines and methods can range from a couple thousand to fifty thousand dollars (or more). A rigger recommended to me always changed the rigging mast up, and did his own swaging on the dock. Would he have done a good job? I’ll never know. Ask your guy who did your swaging, and what machine he used. The finished diameter of each swage is specified by the swage manufacturer: you should check them with your micrometer. Both under and over-compressed can fail.


2. Test the cable you have: the breaking strength of 1/4” 316ss is about 7000 lb, in 304ss about 8500 lb. Most good wire is delivered on a spool with a tag with pull test specification and chemical analysis. Again, ask the rigger. It’s possible your new rigger may be able to do a pull/breaking test.


You could also test the wire against some known 316 with a magnet (the magnet should be equally ineffective on both), but this will be difficult to judge. But if there’s a definite difference and the magnet sticks to your wire but not to the known 316, you don’t have 316.


Junkyard guys use a “spark” test by running an angle grinder against it. Allegedly the 316 spark will stay intact to the end of its flight; the 304 will “fork” at the end – again may not be a clear result. But an easy test. The sparks should be of short flight and red or red/orange. However if you get yellowish, longer flight sparks, it is NOT 316. A few drops of sulphuric acid strongly attacks 304 grade, producing green crystals and a dark surface, but its attack on 316 grade is slow and produces a brown surface


3. Take some good pictures, please!

[captchetco]

Having a background in sailboat repair and marine electrical, I agree that electrically caused or aided corrosion is VERY unlikely. I would bet it is inferior wire. Even 302/4 SS should not corrode noticeably for several years, and 316 frequently lasts 20. Even galvanized lasts many years. If all the failed strands are close to a swaged terminal, improper swaging could be a cause. If someone managed to splash HCL on the wire, that can cause premature failure, but does not look like rust. If you can tell in which country the wire was made, it could tell you the answer. Only remedy is replacement.

[Arrandir]

I have missed your responses since the notifications was sorted out in the spam filter.
Usually I trust someone more who got something as a profession who have seen the problem than people with unknown experience on a forum, but this time it seems to be enough majority to exclude stray current. Even if it wasn't that this time, it's always good to check once in a while with good equipment.
Here are two pictures of how it looked like.
Unfortunately I don't know any details about what kind of SS they used. I have checked the documents I got, it just say that it's from Bluewave and cost 2900 for all material. No list over what they actually used.
The original rigger is far away, but I can bring the boat to another rigger who can check it. I will talk to the first rigger and ask him about what he have used.