ECN Forum Forums Code Related Discussion Building Codes for Electricians anti oxidant on aluminum conductors

I am really confused as to why a power release is being held up because the inspector had a question as to wheather anti oxidant was used on the aluminum conductors of a residential service. I do use it as a personal preference, and this guy must be legally blind, but is there some requirement that I am unaware of? An NEC requirement, or installation instructions that call for it or the use of it to obtain the UL listing of the product are the only reason I know of for an inspector to require its use. Have I missed something? Or are inspectors now pulling the old well thats how we used to do it thing?

I think the inspector has the obligation to justify his violations ... but that just may be me.

You haven't missed anything as far as the NEC is concerned, I'd say you hit the nail on the head with the "well thats how we used to do it thing"

Roger

We recently had a pep talk from an aluminum wire rep, and she asserted that aluminum needed the paste no more than copper wire.

Yet, I am old enough to remember when every failure of an aluminum wire install was blamed, by the wire makers. on the lack of, or improper application of, the paste.

I also note that crimp lugs generally come with some sort of paste in them already.

Since you mention service conductors, what does the local PoCo say?

Trade practice is not really enforceable as law ... there is some room for 'neat and workmanlike' calls ... but I consider using the paste necessary. If nothing else, it removes one future cause for argument. I don't get paid to argue.

IAEI magazine has an article this month about aluminum connections by a guy from Brundy and he says you are supposed to wirebrush the conductor and use the goo. I wonder if it is in their instructions making it a 110.3(B)? I am surprised they didn't specify this since it is a magazine for inspectors. A few months ago I was in an IAEI meeting with the Alcan man and he said the goo wasn't necessary, a properly torqued connector breaks up the oxide and makes a gas tight joint so it won't form again.
I can sure see where the confusion comes from.

Greg, I wonder if Burndy manufacturers a line of inhibitor.;):D

I will go with the Alcan rep.

Roger

A properly torqued connector... makes a gas tight joint ?
Not sure how that works.
The corrosion (green stuff) on copper conducts electricity. The white oxide on Aluminum does not.
When was the last time you saw someone wirebrush the AL before putting it in a connection ?
I'll look for anti-oxide unless there is a written document saying it is not needed.
Alan--

I think you have that backwards. If the NEC does not require anti-oxidant and if the manufacturer does't say you do need it, what will you use as a basis for failing the job?

The way it was explained is when you torq the connector to spec the wire deforms to seal against the lug, creating a gas tight fit, much the way a tapered spark plug or oxygen, acetylene or nitrogen gas bottle fitting can work without a gasket.

BTW if you believe the Burundy guy about the antioxidant why aren't you failing them for NOT wirebrushing the joint. He said that too.

Alan, I agree with Greg.

The NEC doesn't require it and if the manufacturer doesn't include it in their instructions there is no grounds for red tagging the installation.

Roger

From the Canadian Electrical Code
12-118 Termination and Splicing of Aluminum Conductors
(1) Adequate precaution shall be given to the termination and splicing of aluminum conductors, including the removal of insulation and separators, the cleaning (wire brushing) of stranded conductors, and the compatibility and installation of fittings.
(2) A joint compound, capable of penetrating the oxide film and preventing its reforming, shall be used for terminating or splicing all sizes of stranded aluminum conductors, unless the termination or splice is approved for use without compound and is so marked.

Still checking some sources, but;
IAEI NEWS Jan/Feb 2006 issue had an article by Christel Hunter, (senior field applications engineer, B.Sc. engineering physics and electrical engineering) for Alcan Cable which includes information on terminating AL wire.
"If terminating a conductor with a set-screw connector, the bare connector should be wire brushed and an oxide inhibitor applied to the bare conductors." It also states "The screw should then be tightened using a torque wrench or torque screwdriver."
In a more recent article...
IAEI NEWS May/June 2007 article by Jacqueline Silvia with FCI BURNDY in the section "Proper Installation is essential"
Point three "Applied an oxide inhibiting compound to any exposed conductor surface before inserting the conductor into the connector."
If the people making the wire and the people making the connectors say to use anti oxide it sure seems like a requirement for 110.3(B)
We don't get to see the wire brush and Torque tool use, but we can tell if there is anti oxide.
Alan--

Alan, the problem with articles in magazines (regardless of who wrote them) is that they are not enforcible as code.

I do beleive that I have seen some manufacturers recommend using an inhibitor, and if this information is included as part of the installation instructions, then I agree it would be enforcible per 110.3(B.

Roger

The problem I see is these trhings just show up as "recomendations", not requirements.
It seems the wire manufacturers say you don't need it and terminal manufacturers "recommend" it.
Adding the "wirebrush the wire" thing really looks like something added by lawyers. As an installer, prove you did and that will be the out the terminal manufacturer can use if the joint fails.
I would "recommend" it too as an inspector but I am still not sure I could "require" it. I don't know how I could verify that the wire was brushed and if it was "properly" brushed, with the right brush. I know from aluminum welding that you are not supposed to use a steel brush or even a stainless brush that has been used on steel in the past.

One of the sources I'm still waiting to hear from is Alcan Cable.
I have never seen a reel of wire with installation instructions.
Therefore I am going to ask Alcan if they have installation instructions, or just recommendations.
Alan--

Sometimes there's a lot you simply can't "know." In a discussion, a dishonest person can use these uncertainties to keep things undecided indefinitely. After all, what is the meaning of the word "is?"

I mention this because I first saw this dialectic (or should it be 'lie-electric?') used back in the 70's, in the 'great aluminum wire debate."
Shown a failed connection, the aluminum wire makers quickly blamed the installer, and the connectors. The devices weren't listed for aluminum. There was no anti-oxidant used. If used, the anti-oxidant was ineffective because it was applied incorrectly. Screws were tightened too much, or too little.
Nevertheless, while still insisting that there was nothing whatever wrong with their wire, the wire makers decided to change the alloy, and limit production to #6 and larger.

Today, an army of representatives are out there, pounding the pavement, extolling the merits of aluminum wire. They are quick to say that the new alloy has over 20 years of field use and testing, proving it to be no more problematic than copper wire. You need not use anti-oxidant. Torque is critical, they say ... oh, and by the way, Greenlee doesn't know how to make crimpers. Their words, not mine.

I say this in preparation for the following pic, provided by Doug Wells:





Please note the evidence of heat at the connection that also lacks anti-oxidant. True, we have no way of knowing the alloy of the wire. Nor have we a way to verify torque after the connection is made.
We do have the reference to Canadian rules, requiring the use of anti-oxidant.

I'd say this pic is a pretty good argument for the use of anti-oxidant.

Reno, there doesn't appear to be any heat damage to the conductor itself, only the screw. For all we know, this could have been from a previous installation.

I would say there are many connections out there with out anti oxidant that don't even have a discolored screw.

BTW, FWIW, I do use it when I work with aluminum but our preferences and work habits are not codes. The bottom line is, there is nothing as far as any NEC wording requiring it, so unless there is a local code, the inspector is wrong to hold up the final.

Roger

I strongly agree with Roger here.

Unless there are specific instructions from the manufactures of the wire or terminal requiring paste it is optional.

I have installed some GE fused disconnects that required the use of paste when using AL conductors, that requirement was on the door of the disconnect along with the torque and conductor ratings of the terminals.

Thanks for the replys. Most of you said about what I thought you were going to.

UPDATE UPDATE

The building official responded to my question of substantiation on the anti-oxidant question by stating in his letter, " the use of corrosion inhibitors when installing aluminum wiring is both required by the NEC and by manufacturers specifications for installation" then quoting 110.14 as the NEC requirement, and sending me the Alcan Cable (suggested specifications for aluminum alloy conductors for distribution feeder applications with recomendations for connectors) as an additional requirement by the manufacturer for the anti-oxidant.

I don't really know how this relates, as I was using Southwire in a service entrance application, and there was no engineer on this job, nor any such suggested specification written for it. (no plans or specs) It was a service upgrade only.

Oh; and 110.14 as far as I can tell only requires that the lugs be identified and where employed that inhibitors shall be suitable for use and not adversely affect the conductors, insulation, or equipment.

So where oh where is the NEC requirement for the use of anti-oxidant?

Stay tuned for further updates.

It's not, the inspector is simply grasping for straws to save face.

Roger

Section 110.10(B) requires listed or labled equipment to be installed in accordance with any instructions included with the listing.

While only UG or UV conductors need to be listed, most conductors are listed anyway.

When the UL White book is consulted, it turns out: "Conductor Termination Compound — Some connectors are shipped pre-filled with conductor termination compound (antioxidant compound). For non-prefilled connectors, conductor termination compound may be used if recommended by the connector manufacturer as preliminary preparation of the conductor."

The recommendations I have read always prescribe oxide inhibiting compound for damp or wet locations with aluminum wires.

The answer is in the word "may" if it was required the word would be "shall".

In regards to anit oxidant, I "shall" continue to apply it to my aluminum terminations even though there is no real requirement to do so. The reason is it "may" become a damp location due to majority are service drop conductors located inside a 3r meter enclosure and we got humidity and salt mixed in the air we breath here. I find salt built up in some extremely curious places after any big winter surf swell has passed.

... And the lug manufacturer "recommends that you do so but this question was based on what the inspector could make you do using the NEC as a reference.
I agree using the goo is a good idea and if I was inspecting your job I would look favorably on seeing it. I might even ask why you didn't if it wasn't there but I would be on shaky ground tagging it.

I would never use aluminum wiring without gooping it. After experiencing 30 years in the business this is a no brainer.

We replace 3 services a month that used aluminum wiring in a 900 unit apartment complex. All are the result of no anti oxidant. I'm very surprised that some do not think it's necessary.

One of the first journeyman I had the opportunity to work with told me that aluminum was good for two things. Buying and carrying. Since he was a Marine that was in the first invasion wave at Iwo Jima (WWII), I thought I'd listen.

The reason some of us do not see it as necessary is that they have changed the make up of aluminum conductors. Those services you are changing are very likely done with the old alloy and not the new.

Truth be told I do use it for permanent work, I skip it for temps.

I just took a service off a building that was installed in 1972.This building is located about 50 feet from salt water. No goop was used and the Aluminum conductors were as shiny as the day they were installed

At work (PoCo) we don't use anti-oxidant with our connections.
But there is conductive grease inside all of the crimp lugs we use.
Our connection system is in two parts:

• rough up the aluminium strands with a clean wire brush.
• Shove it in the crimp lug and turn it a couple of times, then crimp it.

I've never had an aluminium crimp fail yet and in case you were wondering, the grease does not contain anti-oxidant.

There are several issues to consider when using aluminum for electrical work, most of which have already been addressed by the manufacturers to some degree .

The use of alloys for conductors is strictly limited, because even very low percentages of alloying metals deliberately added [ & not forgetting the inevitable impurities in aluminum originating at the smelter, like silicon and iron ] increase a metal's electrical resistance and susceptibility to corrosion. But aluminum is a very weak metal, difficult to obtain pure because any impurities in the bauxite ore pass into the metal by the only commercial process we have. What is not generally realised is that work-hardened metals have a higher electrical resistance. When drawn through dies, copper wire work hardens so the wire we use is not as electrically conductive as it would be if annealed. Aluminum alloys also age harden naturally [ solid-solution precipitation hardening] which also affects conductivity.


'Anti-oxidant' implies that the join, where the wire changes over to copper wire, requires protection from oxygen. Disimilar metals, in contact and in the presense of an electrolyte can corrode as anode/cathode in an electric cell. The actual electrolyte determines the corrosion- salt water could create chlorides not oxides. You could thus get sulfides, hydroxides, chlorides, carbonates etc. etc.
ALL aluminum surfaces, alloys included, have a thin layer of aluminum oxide on the surface. The metal is extemely reactive, and without this self creating/healing coating would probably burn violently in air!

There are several issues to consider when using aluminum wire for electrical work.

The use of alloys for conductors is strictly limited, because even very low percentages of alloying metals deliberately added [ & not forgetting the inevitable impurities in aluminum originating at the smelter, like silicon and iron ] increase a metal's electrical resistance and susceptibility to corrosion. Aluminum itself is a very weak metal, but difficult to obtain pure because any impurities in the bauxite ore pass into the metal by the only commercial process we have.
What is not generally realised is that work-hardened metals also have a higher electrical resistance than when soft. When drawn through dies, copper wire work-hardens, so the wire we use is not as electrically conductive as it would be if annealed. Aluminum alloys also age-harden naturally, [ solid-solution precipitation hardening ], which also affects the conductivity. This is not easy, is it?

'Anti-oxidant' implies that the join, where the Al. wire changes over to copper wire, requires protection from oxygen. Disimilar metals, in electrical contact and in the presence of an electrolyte can corrode as anode/cathode in an electric-cell. The actual electrolyte determines the corrosion; salt water could create chlorides not oxides. You could thus get sulfides, hydroxides, chlorides, carbonates etc. etc.

ALL aluminum surfaces, alloys included, have a thin layer of aluminum oxide on the surface. The metal is extremely reactive, and without this self creating/healing coating would probably self-ignite and burn violently in air!

So in reality, a freshly made dry, clean join between the two metal conductors, [ using suitable gage wire to suit the properties and usage and using the properly specified connectors and supports] needs to be protected against the contamination and damage by some future arrival of an electrolyte, whether it be damp, salt incursion or otherwise. Vaseline grease would probably be as good as any, provided it were acid neutral, [ ph 7.0 ], just as a physical barrier.

Alan

Alan, great chemical explination, one thing though, "oxidation" refers to ALL reactions where something loses an electron to another thing, even if it doesn't involve oxygen! this is a convention dating back to when these types of reactions were first really theorized about.

As to Trumpy's greasy connections, any non-polar substance will prevent oxidation reactions, for instance sodium, which will BURN in water (well, produce hydrogen and enough heat to ignite said hydrogen) can be stored in oil, and kept lustrous i.e. not corode, it doesn't have to have any "special" anti oxident properties, even plain graphite would work.



-Will

Will, just shows you never stop learning stuff. I must have dived hundreds of times into my inorganic chemistry textbooks, 'Partington' and 'Mellor' continuously over the last 45 years. And blow me down, there it was all the time hiding in a paragraph under reduction and oxidation! [ redox ].

Alan

I too can see where this gets confusing. I would ask the EC to provide me paper work from the wire manufacture stating that the "goo" is not needed, and I would pass the job. Now if the connector people still want the goo, then the job might fail under 110.3(B)Again, I think the manufactures should get together and work their problems out, then notify, UL, IAEI, and contractors as to the correct way to install their products.

Aluminum wire manufacturers recommend goo but, don't require it because they don't make the connectors.
Connector manufacturers recommend it but don't require it because they don't make the wire.
Some connectors are supplied with goo in them because they were evaluated and listed that way.
The Code could be used to resolve the issue by making it a requirement.
Documenting the need fir the goo is a problem because when the terminal fails it leaves almost no evidence of the cause of failure.

as an inspector and a contractor I do not require it but I always use it. I am old enough to remember the nightmares
with AL conductors.