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3yr apprentice
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Discussion Starter · #1 ·
I am trying to find code info and product info on doing proper joints between aluminum and copper wire. My boss was telling me to twist wires together, cover in de-ox and use aluminum marretts. Everything made sense except the aluminum marretts. Because whether you use aluminum or copper approved marretts you still have disimilar metals. I thought maybe it would have to be a special aluminum to copper marrett. But I just having troubles confirming details on proper ways to do this?? Any help is appreciated.
 

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RIP 1959-2015
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I am trying to find code info and product info on doing proper joints between aluminum and copper wire. My boss was telling me to twist wires together, cover in de-ox and use aluminum marretts. Everything made sense except the aluminum marretts. Because whether you use aluminum or copper approved marretts you still have disimilar metals. I thought maybe it would have to be a special aluminum to copper marrett. But I just having troubles confirming details on proper ways to do this?? Any help is appreciated.

Use these http://www.idealindustries.com/products/wire_termination/twist-on/twister_al-cu.jsp

Your boss is right, strip the wire about an inch and twist then together with your linesman's make sure your splice is rock solid then cut it on an angle and twist on your wire nut, DO NOT DEPEND ON THE WIRE-NUT TO DO THE TWISTING, that is your job as an electrician to make up the splice and check it before the wire-nut.
 

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3yr apprentice
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Discussion Starter · #5 ·
Thanks. That ideal website very detailed. I think what threw me off was when I asked the boss why these marrets so special he said it was aluminum inside and the normal ones are copper inside. Which is not the case. The copper approved marretts might be copper coated inside but the aluminum marretts are designed to be more springy to allow the expansion and contraction. That's why they approved for these types of joints.
 

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Electron Pathway Engineer
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3,105 Posts
There are Marrettes made specifically for Cu/Al splices. Can't remember the numbers now.
#'s 63 and 65;)

You don't use antioxidant.
Yes you do, to prevent electrolysis and corrosion= 2 dissimilar metals :thumbsup:

Btw the ones that Black Dog linked already have the anti-ox in them. :D
 

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Alumiconns are returdedly expensive. A box of 100 #63 marrettes is probably $15.. each alumiconn is like $3. I have 1 alumiconn from the "free sample" they mail and I still haven't used it. They seem nice though, but aint no way I'm spending $10 on a single device box to pigtail copper, which I can do it for like $0.50.
 

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No where on the box or specs of the #63 and #65 marrettes does it say to use anti ox,anti ox on stranded al for sure.
You think the connections are inferior if anti-ox is used in the #63 or #65 marrettes splicing aluminum to copper?

I always use anti-ox on aluminum, always, all the time.. so when I do copper pigtails from #63/65's I also use anti-ox.
 

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Nobody says you can't but nobody says you have to.
maybe yes maybe no?

2-112 Corrosion protection for materials used in wiring
(1) Metals used in wiring, such as raceways, cable sheaths and armour, boxes, and fittings, shall be suitably protected against corrosion for the environment in which they are to be used or shall be made of suitable corrosion-resistant material.
(2) Where practicable, dissimilar metals shall not be used where there is a possibility of galvanic action.



Rule 2-112 Corrosion protection for materials used in wiring
In many parts of Canada, salts or chemicals are used on roads to reduce the danger from ice. These salts adhere to vehicles and subsequently drip onto parking areas, pavement, roadbeds, and similar areas, permeating the base material and corroding metals in the floor, pavement, or roadbed. To prevent shorts and shock hazards in conductors and electrical equipment such as raceways or enclosures, Rule 2-112(1) requires that they be protected against corrosion and be suitable for the intended environment.
Dissimilar metals (e.g., copper and aluminum), when in contact with each other in moist or wet environments, can cause galvanic action, which results in one material disintegrating. If this occurs in an electrical connection or electrical equipment, the connection or equipment can fail, causing arcing and shock or fire hazards. Subrule (2) does not allow the use of dissimilar metals where galvanic action between them can occur. In certain cases, however, because of the type of equipment available, the infrequent occurrence of the conditions that give rise to galvanic action, the scheduled maintenance, and the type and strength of corrosive material, Subrule (2) allows dissimilar metals to be present in corrosive environments. Coatings or treatments for the prevention of galvanic action should be used between dissimilar metals. However, coating and treatments can be compromised over time, thus reducing the integrity of the materials.
 

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Estwing magic
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maybe yes maybe no?

2-112 Corrosion protection for materials used in wiring
(1) Metals used in wiring, such as raceways, cable sheaths and armour, boxes, and fittings, shall be suitably protected against corrosion for the environment in which they are to be used or shall be made of suitable corrosion-resistant material.
(2) Where practicable, dissimilar metals shall not be used where there is a possibility of galvanic action.



Rule 2-112 Corrosion protection for materials used in wiring
In many parts of Canada, salts or chemicals are used on roads to reduce the danger from ice. These salts adhere to vehicles and subsequently drip onto parking areas, pavement, roadbeds, and similar areas, permeating the base material and corroding metals in the floor, pavement, or roadbed. To prevent shorts and shock hazards in conductors and electrical equipment such as raceways or enclosures, Rule 2-112(1) requires that they be protected against corrosion and be suitable for the intended environment.
Dissimilar metals (e.g., copper and aluminum), when in contact with each other in moist or wet environments, can cause galvanic action, which results in one material disintegrating. If this occurs in an electrical connection or electrical equipment, the connection or equipment can fail, causing arcing and shock or fire hazards. Subrule (2) does not allow the use of dissimilar metals where galvanic action between them can occur. In certain cases, however, because of the type of equipment available, the infrequent occurrence of the conditions that give rise to galvanic action, the scheduled maintenance, and the type and strength of corrosive material, Subrule (2) allows dissimilar metals to be present in corrosive environments. Coatings or treatments for the prevention of galvanic action should be used between dissimilar metals. However, coating and treatments can be compromised over time, thus reducing the integrity of the materials.
Section 13 says you don't have to.
 

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12-118 Termination and splicing of aluminum conductors
(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.

That being said, I always clean the exposed conductor with Emery cloth or sandpaper, and apply antioxidant compound, for stranded and solid. If it is an older joint that wasn't done properly, there may already be some oxidation.

I use 63 or 65 marrettes.
 
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