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Posted

I call it anti-oxidant "goop". I apply it with a toothbrush (used).

The official name of one brand is...

Ox-Gard Anti-Oxidant Compound

Also what goes along with this, as this is mainly used on main lugs is a torque wrench. The instructions/labels on main panels will say to torque the main lugs (connections) to a certain inch pounds (in. lbs.). And 12 inch pounds equals 1 foot pound.

When you get high amperage connections, the tightness of the connection gets to be very important! You can tighten these quite tight and it is not tight enough! (Depending on your strength.) The connection can become warm/hot if not tight enough. And you can even measure a voltage across a connection which is not tight enough. This is called "voltage drop".

On voltage drop...

http://psihq.com/iread/faqvolt.htm

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Posted

I had a discussion with the lurking "guru" a while back. What he left me with affirms what Billy bob said. The one detail that differs is the installation process. As I remember it, the compound should be applied to wire with emery cloth.

My own thought would be to apply it directly to the set screw for the threaded connection.

The NEC does not require it's use but it is needed to properly torque the set screw. Only some cable manufacturers require it's use on their products. We will loose the war of calling it's omission from AL cable but we can win a war on the proper torquing of the connection.

Posted

So, its main purpose is to provide lubrication for proper torque of the main lugs? I didn't know that.

No. Its main purpose is to prevent a film of oxide from forming on the aluminum. When you cut or scratch aluminum wire, a coating of aluminum oxide begins to form immediately. Since aluminum oxide is an electrical insulator, we don't want it on our connections. The functional part of the paste is really just grease. It keeps the air away from the aluminum.

Really anal retentive electricians will strip the wire, apply the paste, and then use a small wire brush or emery cloth to abrade the aluminum so that they expose fresh metal that's submerged in the paste, so that the freshly exposed metal never comes in contact with the air.

Lots of electricians also apply the paste to the lug's screw threads for lubrication, so that they can torque the connection properly. A few electricians in my area also daub some of the paste on the bus bar tongues to make the breakers slide on more easily. This is getting into some pretty suspect territory; some people feel that the paste qualifies as a contaminant and has no business being on the bus bar.

- Jim Katen, Oregon

Posted
This is getting into some pretty suspect territory; some people feel that the paste qualifies as a contaminant and has no business being on the bus bar.

Some breakers come from the factory with grease in the stab area.
Posted

I should have made the torque comments more clear.

The torquing is separate from the anti-oxidant. For example you would torque a copper wire and not apply anti-oxidant.

I was just saying a "good install" would include anti-oxidant if aluminum *and* torquing.

What happens if you don't do either is the connection can get hot/cool, hot/cool, etc. as you turn things on/off. Then eventually the connection can work its was loose and you can lose power entirely.

Posted

This is getting into some pretty suspect territory; some people feel that the paste qualifies as a contaminant and has no business being on the bus bar.

Some breakers come from the factory with grease in the stab area.

Sure, but I'm pretty sure that isn't anti-oxidant paste. I believe it's silicone grease and it's there purely as a lubricant.

As a working electrician, what's your opinion of the practice of applying anti-oxidant paste to the bus bars?

- Jim Katen, Oregon

Posted
Sure, but I'm pretty sure that isn't anti-oxidant paste. I believe it's silicone grease and it's there purely as a lubricant.
Could be, but I have seen and have de-ox that is clear and grease-like, just like what you'd see on a breaker.

I'll have to check. If I find out for sure I'll post it.

As a working electrician, what's your opinion of the practice of applying anti-oxidant paste to the bus bars?

I only do this with aluminum busses in outdoor panels or where the panel is in a high humidity environment.
Posted

Sure, but I'm pretty sure that isn't anti-oxidant paste. I believe it's silicone grease and it's there purely as a lubricant.
Could be, but I have seen and have de-ox that is clear and grease-like, just like what you'd see on a breaker.

I'll have to check. If I find out for sure I'll post it.

Oh yes, certainly. Some of the anti-ox compounds are clear. There are clear blue, amber, and clear versions as well as the ugly opaque GB black stuff. However, I'm pretty sure that the stuff that the manufacturers pack in the breakers isn't one of those. I think it's a different product -- I don't really know though.

As a working electrician, what's your opinion of the practice of applying anti-oxidant paste to the bus bars?

I only do this with aluminum busses in outdoor panels or where the panel is in a high humidity environment.

Makes sense. Thanks.

- Jim Katen, Oregon

Posted

I know a few electricians who use it on Copper mains as well just to have the lubrication between the lug screw and the wire while tightening. They say it prevents the screw from tearing up the wire. Sounds reasonable...

I've heard it called all manner of things from anti oxidant to oxide inhibitor and even monkey shit. The latter term of endearment belonging to a specific brand, Penetrox, which looks and smells close enough. Also one of the best products IMHO, one of the few that won't burn readily and support a flame.

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