Using Copper and Aluminum Wire for Home Circuits

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When splicing aluminum and copper wires do the wire connectors need to be a special type? Wiring Methods for Copper and Aluminum Wires, Safe uses of Aluminum Wire for Larger Home Electrical Circuits.

Copper and Aluminum Wiring

Electrical Question: When splicing aluminum and copper wires do the wire connectors need to be a special type?
I am replacing a ceiling light fixture and I have questions about some aluminum wire I am working with.

  • The new light fixture has two 60 watt bulbs and will be on a 15 amp circuit.
  • The original light fixture’s copper black wire is connected to a single copper black wire, which is dropping down from the attic and into a wire nut.
  • The current fixture’s single copper white wire is connected to four other white wires in a large black wire nut.
  • The new light has both black and white wires of stranded aluminum and comes with orange wire nuts.
  • The manufacturer’s 800 number says that the supplied orange wire nuts are fine for this light’s copper-aluminum connection.

CU/AL Splice Connectors for Copper and Aluminum Wire

  1. Do one or the other or both connectors need to be special CU/AL connectors such as Ideal Twister? For instance, can the neutral group remain within a standard connector?
  2. If standard connectors are OK, can I still use the current large black connector to twist the light’s neutral aluminum strands with the other four neutral coppers?

Thanks for any assistance you can give.

This electrical question came from: Joe, a Homeowner from Woodridge, Illinois.
Dave’s Reply: Thanks for your electrical question Joe.

Wiring Methods for Copper and Aluminum Wires

Application: Splicing Electrical Wires.
Skill Level: Intermediate to Advanced – Best performed by a Licensed Electrician.
Tools Required: Basic Electricians Pouch Hand Tools and Voltage Tester.
Estimated Time: Depends on the personal level experience and ability to work with tools and access to the wiring.
Precaution: Identify the circuit, turn it OFF and then Tag it with a Note before performing any wiring.
Notice: Installing additional electrical wiring should be done according to local and national electrical codes with a permit and inspected.
Materials: Properly sized wire connectors, anti-corrosion ointment, electrical tape, junction box and blank cover.

Working with Copper and Aluminum Electrical Wiring

  • Electrical Answer specific to this question

    • In the example of this question, the fixture wires are most likely tinned copper wires, not aluminum wires, so they may have the appearance of aluminum wires but they are not.
    • Stranded wire and solid wire may be spliced together when using wiring connectors that are approved for both types of wires.
    • This electrical question appears to describe light fixture wiring that is not brought directly into a light fixture  without a junction box or fixture box. If the new light fixture does not have an approved self contained wiring enclosure then a fixture box should be installed to provide a proper splice enclosure of the electrical wires.

Installing Aluminum Wiring for Home Electrical Circuits

Safe uses of Aluminum Wire for Larger Home Electrical Circuits and the Advantages of Copper Wire for Home Electrical Circuits.

  • Restrictions of Aluminum Wiring for Homes

    • The electrical code once allowed homes to be wired with aluminum wire, and at that time it was allowed for #12 aluminum wire to be used for 15 amp circuits, however that is not longer permitted or allowed.
    • Many home and mobile home fires have been linked to the use of aluminum wiring, especially with branch circuits for lighting and receptacle outlets.
  • Approved Aluminum Electrical Wiring for Homes

    • The installation of permitted aluminum wiring must still be acceptable by your local building department.
    • Areas that are near the ocean were salt will affect then integrity and connections of aluminum wire will have restrictions on the installation of aluminum wiring.
    • In areas where aluminum wire is permitted the installation must be followed according to the electrical codes.
    • One example of the code states that for standard over current device sizes, use for protection of a  non-motor appliance,  a 45 amp circuit with #6 SE Aluminum cable may be used.
  • Safe Uses of Aluminum Wire for Larger Home Electrical Circuits
    • Aluminum wire may be used where permitted and as indicated  by the electrical code and installed according to the provisions that ensure safety and circuit integrity, including the use of non-corrosive compounds, and approved terminals or wire connectors for use with aluminum wire.
  • Advantages of Copper Wire for Home Electrical Circuits

    • Without a doubt, copper is a very good choice for electrical wiring.
    • It is common to see that some of the larger loads state that copper wire is required, such as for hot tubs and many air conditioners, and other equipment.
    • Copper offers less resistance and does not expand and contract under load like aluminum wire does, which is a major cause of circuit connection failures.

More about Splicing Electrical Wires

Guide to Home Electrical Wire

Electrical Wire for the Home

Complete listing of electrical wire types and parts used for home projects with electrical code information serves as selection guidelines.

Splicing Electrical Wires

Electrical Junction Box Splice

Electrical junction box splices can be made safely when you understand the method. This example will show you how its done step by step and shows how to make a junction box splice and the related electrical codes.

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Be Careful and Be Safe - Never Work on Energized Circuits!
Consult your Local Building Department about Permits and Inspections for all projects.


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FAQs Frequently Asked Questions and Comments

4 Responses to “Using Copper and Aluminum Wire for Home Circuits”
  1. Dave Rongey says:

    Hi Robert,
    You are correct, however I did mention that CU and AL wire splices should be done with the use of non-corrosive compounds, and of course there are a few approved brands available including the one you have mentioned.
    I always appreciate a fellow Sparky adding their comments – Thanks!

  2. Robert says:

    Dave, I reading this response to CU and AL where code accepted I note that you did not mention the use of Noalux when wiring AL to CU?

  3. Dave Rongey says:

    Hi Kiri,
    The electrical code states that either aluminum or copper wire conductors may be installed for cook tops. The size of the wire and amperage must be adequate for the specific cook top you have.
    That being said, there are manufacturers of equipment who specifically require a copper wired circuit, however I have only seen this on motor type equipment such as air conditioners, well pumps etc..
    I would consult the manufacturer directly to make sure as to not void the warranty and make sure the cook top will perform correctly.

  4. Kiri says:

    We are remodeling our kitchen in Rochester, NY. We are replacing an electric cook top with an Induction cook top, also replacing a wall oven. The present wiring from the breaker panel is heavy gauge aluminum. Do we have to replace the aluminum wire with copper?. what is the code in effect.
    Thanks, Kiri


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