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Topic: Ground wires. Rust. Follow up. (Read 15 times) previous topic - next topic
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Ground wires. Rust. Follow up.
Yahoo Message Number: 159698
Just got off the phone with Vince. Here is what I am seeing near the steps on the TK. The location of these grounds will vary with the model.

The bare solid copper wire , #10, is the "main chassis ground".
The stranded wire near the generator is the ground for the generator.

We discussed the rusting of the screw I talked about in another post. Since this failure happened in less than a year, road salt is the prime suspect. Galvanic corrosion certainly, but not in this short a time period.
His objection to stainless screws In situations like this where the connection needs to be really, really tight is that stainless is brittle and might snap when being installed.
We discussed using a stainless nut and bolt to replace the failed screw. He thought that would work well as long as star washers are used to insure a good contact with the frame. Plus, of course, cleaning all contact points well and then using the red spray (don't know the proper name of it) like is used on battery terminals, to keep salt water off the hardware.

So.
If you live, or travel in, snow country, you might want to inspect the grounds now and then.
LD sees no need to change the current procedure to address such a rare occurance.

Ed
Re: Ground wires. Rust. Follow up.
Reply #1 –
Yahoo Message Number: 159699
Thanks for the follow-up, Ed; useful information, particularly for those who live in "salty roads" areas.

Joan

P.S. I wasn't aware that stainless steel screws were "brittle"; ???
2003 TK has a new home
Ground wires. Rust. Follow up.
Reply #2 –
Yahoo Message Number: 159935
"I wasn't aware that stainless steel screws were 'brittle'..."

I don't know about that, but I do know that stainless steel is a relatively poor conductor of electricity. For that reason it's not recommended for electrical connections, because it can cause overheating due to its poor conductivity.

Another thing about stainless steel that I didn't know until recently is that it's prone to "galling" when there's stainless-on-stainless contact, as when a stainless bolt goes into a stainless nut. The two pieces can essentially friction-weld together, and once that happens, nothing can get them apart without damage. (When mixing stainless fasteners with those of other metals, galling is unlikely.)

This happened to me last year with my AM Solar panels, which are fastened to their tilt mounts by stainless steel knobs going into stainless steel nut inserts in the mounting brackets. I was removing one of the knobs in order to un-tilt the panel when it jammed, and no power on earth would get it un-stuck. I had to hacksaw it off, then remove and discard the mounting bracket as well as the knob. I was lucky that AM Solar still had a few spares for sale.

A couple of months later, the same thing happened on another panel. This time I took decisive action: I ordered 1/4-20 bronze machine screws and plastic knob heads from McMaster-Carr, assembled my own knobs, and replaced all twenty mounting knobs on my five panels. Bronze on stainless won't gall.

(An alternative would have been to lubricate the threads of the stainless fittings with Tef-Gel, which prevents galling. But I felt more comfortable replacing the knobs altogether, since they were ten years old.)

I had always thought of stainless steel as the perfect metal... until I started talking with friends who had boating experience. Now I realize that like everything else, it has limitations.

Andy Baird
As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"