Circuit Panel power

[hmurmur]

I recently lost power to the circuit panel. Turns out the power to the panel is supplied by a red wire. The wire is secured to the panel by a screw with a washer and nut. It is not screwed into the panel. There is a round ring of metal on the circuit board that the screw contacts via the washer. Can I reasonably use a stainless washer to secure with a lock washer and nut?
This seems like a method bound to fail, as it did once already!
Suggestions please!
2016 Oceanis 48

 

[DougM]

I would not suggest using stainless. Stainless steel (at least good stainless) is a non conductor.

 

[LeslieTroyer]

Can you post a photo. I’m having a problem visualizing the setup.

Is there a ring terminal on the red wire or is it just squeezed between the trace on the circuit board by the washer and machine screw and nut???

 

[dlochner]

Can you post a photo. I’m having a problem visualizing the setup.

Me too.

I would not suggest using stainless. Stainless steel (at least good stainless) is a non conductor.

If the SS is to be a conductor, then @DougM has a good point. If the SS screw only holds the terminal to a better conductor, then SS isn't so bad as it is not a conductor. Same as on the battery, the SS washer and nut only hold the terminal against the better conducting lead post.

 

[jviss]

Stainless steel (at least good stainless) is a non conductor.

That is completely incorrect! Stainless is a fairly good conductor, and many marine electrical systems use it in various ways. The most common you'll encounter are the nuts and washers on battery posts. Not as good as copper, of course.

(On the IACS scale, for which the conductivity of annealed copper is defined as 100%, 314 stainless is 2.5%, or 1/40th of the conductivity of copper.)

 

[dlochner]

That is completely incorrect! Stainless is a fairly good conductor, and many marine electrical systems use it in various ways. The most common you'll encounter are the nuts and washers on battery posts. Not as good as copper, of course.

(On the IACS scale, for which the conductivity of annealed copper is defined as 100%, 314 stainless is 2.5%, or 1/40th of the conductivity of copper.)

I'm confused. On the one had you say that SS is fairly good conductor, but then you say that it has 1/40th the conductivity of copper. These 2 statements seem incompatible. Am I missing something?

 

[jviss]

1/40th the conductivity of copper is still a good conductor! It's pretty close to the conductivity of plain steel.

 

[LeslieTroyer]

In your case it doesn’t matter so it’s a non issue the vast majority will flow between the ring terminal and circuit board ignoring the nut screw and washer ( unless there is a power pad on the other side of the board).

If there isn’t a ring terminal on the red wire - install one. And use a lock washer or nylock nut.

Les

 

[jviss]

Look at it this way. The difference in the resistance of the thickness of a stainless steel washer versus a copper one is not detectable in the field, i.e., with a regular VOM. You would need very sensitive laboratory equipment. So, day one, virtually the same. After a few years in a corrosive atmosphere, the copper will oxidize and corrode, and could well be more resistive at that point.

 

[CaptKimble]

If stainless was a bad connector then the major electrical suppliers would never use it to make buss bars and switches. Just my 2 cents worth.

 

[Maine Sail]

If stainless was a bad connector then the major electrical suppliers would never use it to make buss bars and switches. Just my 2 cents worth.

Good manufacturers don't use stainless as the conductor unless it is grossly oversized. They use plated brass or copper and the stainless nut & washer is only used to compress the lug or terminal to the plated brass or copper busbar...

The two most widely used busbars in the industry, Blue Sea and Marinco ProInstaller are made of tin plated copper...

 

[CaptKimble]

Thank you MaineSail. I was aware that the hardware was stainless but did not know that the busbars were tin plated copper. Good to know stuff as usual. We just had a discussion here in the shop about what we have in our aircraft ( we are a major manufacturer repair station ) and at first we thought they were made of CRES (corrosion resistant steel) but we finally decided to bite the bullet and look it up in some of the drawings. It made for a very informative break time. We are all trying to find some drawing that will give us a definitive answer.