conductivity

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reginald watkins

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Please assist in a difference of opinion. I was explaining to another electrician that not only was Noalox or Penatrox an antioxidant but it was also conductive and therefore provided for the transference of current.
 
I am sure that Noalox is conductive otherwise you would not be allowed to put it on the conductor. If you are saying that Noalox must be used for conductivity then I would disagree.

With the aluminum conductors of today Noalox is not even required. I believe Southwire recommends Noalox even on copper conductors.
 
A 'termination compound' (don't know if that is the proper term) need not be conductive. It simply needs to get squeezed out of the way when the termination is made up.

It is quite common to use 'dielectric grease' on connections used in automobiles and outdoors. This is a non-conductive material but the circuits work. (Note that the practice is not necessarily a good one; a topic for a different discussion; I simply want to point out that the connections _function_.)

Ideal makes the claim for Noalox that 'Suspended zinc particles penetrate and cut aluminum oxide'
( http://www.idealindustries.ca/products/wire_installation/accessories/noalox.php )

The zinc would be a conductor, but the compound as a whole is likely an insulator; any improved conductivity would be caused by breaking through the aluminum oxide where you have metal to metal contact.

-Jon
 
I think all those added metals are snake-oil: The grease is not part of the current-carrying path.

One of the most common lubricants on conductors in high current circuit breakers is a clay-based machine grease. It has no special electrical abilities yet works great.
 
If grease is not conductive then it is an insulator???????? Obviously that is not true but how can you coat a lug with grease when that lug is the point of contact between the wire and the lug. I am confused
 
I coat to my battery terminals with petroleum jelly. It is not conductive. But it provides protection against external contaminants. Therefore coating does not necessarily need to be conductive.

Sent from my SM-G900V using Tapatalk
 
Dennis Alwon said:
How can you coat a lug with grease when that lug is the point of contact between the wire and the lug?
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I ain't a scientician, but I think it's because the electrical connection occurs between thousands of microscopic hills where metal-to-metal contact occurs between the conductors regardless of what fills the valleys between the surfaces.

When conductors are really sandwiched together I think those microscopic connection points tend to punch through easily-displaced grease.
 
big john said:
I ain't a scientician, but I think it's because the electrical connection occurs between thousands of microscopic hills where metal-to-metal contact occurs between the conductors regardless of what fills the valleys between the surfaces.

When conductors are really sandwiched together I think those microscopic connection points tend to punch through easily-displaced grease.
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Thank you -- I get your jist but I get wrapped around the idea that the grease is an insulator therefore curent can't flow or is impeded. If I could someone suspend water around the conductor wouldn't the wire not conduct as well-- depending on the water chemicals etc. I see this as similar- I understand and believe you that it works-- people use vaseline around light bulb ends to make them easier to come out-- I just don't get the thousands of hills-- I am assuming the wire is totally covered
 
I'm not sure if it's a valid analogy, but think of air: Air is an insulating fluid that surrounds the conductors. Yet they still pass current when connected together, despite air trapped between them.

Grease is just a more viscous fluid that's also trapped between the conductors.

Obviously there is a point where this idea begins to break down and you *will* develop a higher resistance connection.
 
big john said:
I'm not sure if it's a valid analogy, but think of air: Air is an insulating fluid that surrounds the conductors. Yet they still pass current when connected together, despite air trapped between them.

Grease is just a more viscous fluid that's also trapped between the conductors.

Obviously there is a point where this idea begins to break down and you *will* develop a higher resistance connection.
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\

I see the analogy but I see that as the same because where the conductor is tightened against the terminal is there air there? Wouldn't the air be pushed aside
 
big john said:
Obviously there is a point where this idea begins to break down and you *will* develop a higher resistance connection.
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And that point comes when the surface tension, viscosity, and other properties of the grease under high PSI contact pressure are sufficient that none of the metal of the two surfaces comes into actual contact.
The hills and valleys analogy is a good one, but under high enough pressure not even a molecule thick layer of the insulator will be left between two smooth metal surfaces.
 
Knuckle Dragger said:
I do not believe Noalox is conductive.
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An anti-oxidant is just what the name implies....a substance to reduce or eliminate oxidation of connections. Conductivity is irrelevant. Back in the day, trailer fires were common because of aluminum wiring. Aluminum oxide is an insulator, so the more oxidized the connection (accelerated by heating), the more the heat, thus the worse the connection 'till smoke and flames. Aluma-Lox is specifically for aluminum conductors. Not recommended or required for copper. Other products are for copper, but I don't think they really do anything. But as stated above, newer aluminum is plated, reducing or eliminating the need for grease. But lots of folks still use it. Old habits die hard. If you've ever had to clean the dried black gunk left behind on a meter or CT panel bus bar connection loaded with Alumalox, you'll learn to hate it, and I have never come across a bolted busbar connection that overheated due to oxidation. Usually a loose bolt! I know UG rated connectors have grease in 'em, but they can be in direct contact with water, so that may be a different story. Inline splices used on many utility lines also contain grease, but they are exposed to the elements in open air.
 
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I don't believe you would want it to be conductive, or else if it dripped on a hot day, it could conduct between places you didn't want.:p
 
meternerd said:
... I know UG rated connectors have grease in 'em, but they can be in direct contact with water, so that may be a different story.
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That's exactly right. It keeps the water from reaching the metal inside the connector after the connection has been made up. It also keeps it from wicking down inside the insulation, so don't strip the wire too long.
 
Dennis Alwon said:
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I see the analogy but I see that as the same because where the conductor is tightened against the terminal is there air there? Wouldn't the air be pushed aside
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In the areas of physical metal to metal contact, yes, just like non-conductive grease would be.
 
reginald watkins said:
Please assist in a difference of opinion. I was explaining to another electrician that not only was Noalox or Penatrox an antioxidant but it was also conductive and therefore provided for the transference of current.
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So why didn't you just tear a piece of cardboard off some packaging and lay a 1" long bead of it on the cardboard and have him test it with a meter to see for himself?
 
Dennis Alwon said:
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I see the analogy but I see that as the same because where the conductor is tightened against the terminal is there air there? Wouldn't the air be pushed aside
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Yes, to a degree. Air still occupies the voids caused by mating surface imperfections. Besides, how much contact do you think two round wires have with each other?!

Anyway, the same principle applies with the grease. At the point of contact, the grease is displaced. What little is left has, in most cases, insignificant resistance. This is also where the metal particles come into play, and settle into the smallest mating surface imperfections.
 
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