anti oxidant cream

[renosteinke]

This topic seems the subject of more double-talk and lawyer-speak than a political convention .... especially on the part of the amulinum wire makers!

I remember, all too well, the heyday of aluminum wire in branch circuits. There was a great deal of pontificating about the high-resistant oxide film forming on aluminum wire, and the absolute need for anti-oxidant when aluminum wire was used.

The IAEI, every month, ran news stories of problems associated with aluminum wire, and the 'lack of proper installation" -meaning inadequate use of anti-oxidant- was the primary excuse given by the aluminum wire makers.

Today we see the aluminum wire makers -again- passing the buck, and saying it's up to the connector manufacturer to recommend it. As in the Southwire link, the makers assert that aluminum needs anti-oxidant no more (or less) than copper. They even state the the routine use of the paste with copper is 'good workmanship.'

Balderdash. NECA standard 104-2006 is a good example. ("Aluminum Building Wire and Cable")
Section 3.2 makes reference to joint compound being used 'where needed to retard oxidation' for any type of wire, including copper. Left out of 3.2 is the assumption, in every other part of the same standard, that joint compound will be used for every other sort of connection.
The same standard includes instructions, with every joining method, to wire brush, coat, connect, and remove excess joint compound.
Oddly enough, such instructions appear only in the aluminum standards. It's certainly absent from the NECA 'good workmanship' standard.

Now, the Achilles' heel of this requirement is that NECA standards are not enforceable as code. Nor, for that matter, is 'good workmanship.'

T&B has a line of marettes (wire nuts) that are CSA approved for aluminum wire, and are used without joint compound.

So, we have a conundrum.
The use of joint compound is a trade practice, with a history of being deemed necessary. Yet, the 'code' position is very weak. While denying any failure of their products, the aluminum wire makers today assert that their wire does not NEED the compound. Testing and approval of connectors, without the use of compound, seems routine.

Absent a specific code citation, I would have to say that the use of compound is not something that can be enforced.
Maybe we need the NEC to specifically address this matter. Proposals, anyone?

 

[iwire]

Maybe we need the NEC to specifically address this matter. Proposals, anyone?

Sounds to me like a design decision, not a code one.

 

[renosteinke]

It sure looks that way.

For those who want to assert that you MUST use the compound ... I think you'll need to get a specific code requirement added.
Ditto on the subject of aluminum wire for branch circuits. Just because the makers "happened" to stop making aluminum wire in sizes smaller than #6 doesn't mean they won't return to the market. Yet, I see no code basis for not allowing the use of such a product.

It won't be long, and all the horror stories from the 70's will be just a distant memory. This sets the stage for a repeat.

If one wishes to mandate the use of the joint compound, or ban the use of aluminum wire .... until it's in the code, that's just an opinion.

 

[weressl]

yep they make compounds for both aluminum and copper..

110.14 Materials such as solder, fluxes, inhibitors, and compounds, where employed, shall be suitable for the use and shall be of a type that will not adversely affect the conductors, installation, or equipment.

yep it is only required by the manufacturer..but it is for the customers benefit to use inhibitors..it helps save the connections..we have one we are dealing with now that is going to cost about 5 grand to improve because everything is corroded and wrecked...it feeds 3 buildings and the original installer never used any inhibitors..good for us bad for customer..

Anti-oxidant fillers are not required for properly installed terminations unless specified by the terminal manufacturer. It reduces the thermal dissipation capability of the wire-lug installation therefore the vital mating points will get hotter, accelerating the oxidation. Anti oxidants are necessary where the assembly or the material itself results in the inability of the connection to compensate for the thermal expansion. When the connection is made up improperly, eg. insufficent pressure was applied, then the anti oxidant compound will slow down - but will not prevent - the development of the hot spot.

 

[LarryFine]

Sounds to me like a design decision, not a code one.

So, Bob, in your opinion, is the routine use of anti-oxidant required for aluminum conductors by the NEC?

(Yes, I do value your opinion. I wouldn't bother debating with you otherwise. )

 

[LarryFine]

Anti-oxidant fillers are not required for properly installed terminations unless specified by the terminal manufacturer. It reduces the thermal dissipation capability of the wire-lug installation therefore the vital mating points will get hotter, accelerating the oxidation. Anti oxidants are necessary where the assembly or the material itself results in the inability of the connection to compensate for the thermal expansion. When the connection is made up improperly, eg. insufficent pressure was applied, then the anti oxidant compound will slow down - but will not prevent - the development of the hot spot.

I thought the purpose of the compound was to minimize oxidation by keeping the contact area more gas-tight, and reducing the heat caused by the resistance of the oxide layer.

In other words, it sounds like you're saying the heat is a cause, and I've always believed it to be a result. I may be misunderstanding your point, but then, this wouldn't be my first time.

 

[jetlag]

ahj call

ahj call

everyone seems to be forgetting the ahj can call for the anti oxidant if they want, and around her they will call you every time. I do agree that the code should be more clear if ahj s are going to keep calling. That reminds me I removed some compression type lugs from a j box that had been in use for years. They had connected #2 alum to #2 cu . They used plain copper lugs and didnt use the al/cu ones with the seperation bar in the middle. Guess what they had some type of grease on them and every thing looked as good as new when taken apart, no sign of corrosion. Since then I needed to connect some 4/0 alum that had been cut . I had a large cu lug . I just filled it full anti oxidant . Im not worried since seeing the one that had been there for years.And way in my case the to alum conductors are compressed together even if the cu lug against the alum is not good.

 

[Mule]

Im sorry this post just made my chuckle as I remembered a mechanic I used to work with in a rotating equipment/motor shop. He used anti-seize on every thing, and lots of it. So much, that everyone noticed at lunch time that he got it all over the white bread on his sandwich on a daily basis. Barf....

He brought a motor stator back to me one day as he just got it out of the washer, and you guessed, anti-seize all over my motor.......I then asked him if his wife was also covered with it.....haha....and I got this deer in the headlights looks.:smile:

 

[LarryFine]

He used anti-seize on every thing, and lots of it. So much, that everyone noticed at lunch time that he got it all over the white bread on his sandwich on a daily basis. Barf....

I bet he never got constipated.

 

[weressl]

I thought the purpose of the compound was to minimize oxidation by keeping the contact area more gas-tight, and reducing the heat caused by the resistance of the oxide layer.

In other words, it sounds like you're saying the heat is a cause, and I've always believed it to be a result. I may be misunderstanding your point, but then, this wouldn't be my first time.

Properly designed and installed connectors will be gas-tight by themselves.

The proper design assures that the thermal expansion/contraction is compensated and that the gas-tightness and conductivity remains the same. Proper installation assures that the initial required pressure is developed.

Due to the metallurgy of the original aluminum wires the design was not able to sufficiently compensate for the thermal expansion and in the contraction phase the wire would not return to its original place. Hence gas(oxigen) was able to enter the gap and initiate oxidation. Aluminum oxide being a poor conductor would result in an increased overall resistance of the connection, resulting increased heat and thus the deteriorating cycle begun and continued until arcing and burnout of the connection.

So applying an anti-oxidant compound will compensate for poor design and sloppy installation and MAY prevent or delay the development of hot spots.

In general I am averse to measures that accept failure and attempt to compensate for it rather than demanding that the design or the installation to be fixed.

 

[raider1]

everyone seems to be forgetting the ahj can call for the anti oxidant if they want, and around her they will call you every time. I do agree that the code should be more clear if ahj s are going to keep calling. That reminds me I removed some compression type lugs from a j box that had been in use for years. They had connected #2 alum to #2 cu . They used plain copper lugs and didnt use the al/cu ones with the seperation bar in the middle. Guess what they had some type of grease on them and every thing looked as good as new when taken apart, no sign of corrosion. Since then I needed to connect some 4/0 alum that had been cut . I had a large cu lug . I just filled it full anti oxidant . Im not worried since seeing the one that had been there for years.And way in my case the to alum conductors are compressed together even if the cu lug against the alum is not good.

No, the AHJ can't just require the anti-oxidant unless it is part of the lugs installation instruction or part of an adopted code. The NEC does not require the use of anti-oxidants unless they are require by the manufacture of the lug.

I personally would never use a non-AL rated lug to connect alum conductors.

Chris