Not Enough Space in Electrical Boxes for Aluminum Wiring Repair using Pigtailing? InspectAPedia® -
How to make space in electrical boxes to fit copper pigtails and connectors on aluminum wiring
How to reduce the risks associated with aluminum electrical wiring
Aluminum wire repair method details and aluminum wire repair products are described here
Aluminum to copper pigtailing & aluminum to aluminum wire splices are here
InspectAPedia offers impartial, unbiased advice without conflicts of interest.
We will block advertisements which we discover or readers inform us are associated with bad business practices,
false-advertising, or junk science. Our contact info is at
InspectAPedia.com/Contact.htm.
This article describes options for fitting copper pigtail wires and wire connectors into electrical junction boxes where solid conductor aluminum electrical wiring is installed. This article describes the acceptable methods to repair aluminum wiring, including which aluminum wire connectors to use for safest results. Readers should be sure to see ALUMINUM WIRING, HOW TO REDUCE THE RISK.
Not Enough Space in the Electrical Boxes to Use Copper Pigtailing on Aluminum Wire?
Technical note on limited space in electrical boxes when pigtailing copper to aluminum electrical wiring: Both the AlumiConn™ and the COPALUM™ connectors (as well as the not-recommended Ideal65 purple Twister™) occupy about the same volume of space during aluminum wiring repair by pigtailing copper to aluminum wires.
In some cases there may be so little free space inside the electrical box that it is difficult to push the pigtailed wires and device back into the wall safely and without damaging or loosening connectors.
Our photo (left) shows an improper "aluminum and copper" wire repair using double-tapping under a single circuit breaker screw. The CU-AL rating stamped into the circuit breaker may itself not have been based on independent testing but more, it is unlikely that the manufacturer intended the circuit breaker to handle both AL and CU wires at once.
There was plenty of room in this electrical panel to use one of the recommended copper-to-aluminum connectors to repair this aluminum wire. But in electrical boxes for wire splices, switches, and receptacles in a building, space may be more limited. Options to handle the limited space for copper to aluminum pigtail wires and connectors include:
Use thinner (front to back) electrical devices: switches and electrical receptacles may be available that are thinner in their front-to-back dimension, making it easier to add the copper to aluminum pigtails and connectors and still push the switch or receptacle back into the wall.
Install electrical box extensions - using a "side car" screw-on box extender or, if the box is deep-set into the wall, a box depth extender, it is possible to add several cubic inches of space to an existing electrical box without necessarily opening the wall itself.
Install a larger cubic-inch electrical box - this step is most disruptive as it means opening the wall cavity at each location where space inside the existing electrical box is inadequate for aluminum wire repairs. T
his approach is reasonable if just one or two of these cases occurs, but if most of the electrical boxes are too small at a building the repair cost may be significantly increased if you have to install many larger electrical boxes.
Even if you intend to gain the needed space by installing a deeper electrical box that is the same in width and height (as opposed to a box that is also wider or taller), the labor will be increased by the work of removing the old electrical box and disconnecting its wires in order to install a new retrofit-type and deeper electrical box.
GFCI devices and aluminum wiring repair: If you are retrofitting a GFCI electrical outlet as well as repairing aluminum electrical wiring at a building, because GFCI devices are generally larger than standard electrical receptacles, you may find that it is impossible to push the GFCI back into the electrical box along with the copper pigtails and connectors.
In this case you should consider using a conventional (non-GFCI) electrical receptacle or even a thinner (front-to-back) electrical receptacle in that location. Provide ground fault protection(GFCI) (or arc fault protection - AFCI) by installing a GFCI or AFCI circuit breaker in the electrical panel to supply electrical power to that circuit.
Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
Additional technical contributors & reference sources for this article are listed below.
Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
Dr. Jess Aronstein, protune@aol.com is a research consultant and an electrical engineer in Poughkeepsie, NY. Dr. Aronstein provides forensic engineering services and independent laboratory testing for various agencies. Dr. Aronstein has published widely on and has designed and conducted tests on aluminum wiring failures, Federal Pacific Stab-Lok electrical equipment, and numerous electrical products and hazards. see Aluminum Wiring Bibliography and see FPE HAZARD ARTICLES, STUDIES for examples.
"The Influence of Corrosion Inhibitor and Surface Abrasion on the Failure of Aluminum-Wired Twist-on Connections",
Aronstein, J.; Campbell, W.,
Components, Hybrids, and Manufacturing Technology, IEEE Transactions on
Volume 7, Issue 1, Mar 1984 Page(s): 20 - 24
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Recommended books on electrical inspection, electrical wiring, electrical problem diagnosis, and electrical repair can be found in the Electrical Books section of the InspectAPedia Bookstore. (courtesy of Amazon.com)
How to Reduce the Risk in buildings with Aluminum Electrical Wiring - Overview of Acceptable Repair Practices (in the document you are presently viewing)
Aluminum Electrical Repair Method Details - "How to" details, how to identify, COPALUM repair, alternative repairs, history, products, research, source of special AMP TYCO COPALUM connectors & COPALUM Electricians (in the document you are presently viewing)
COPALUM Electricians: Sources of TYCO COPALUM -Certified/Trained Aluminum Wire Repair Services (in the document you are presently viewing)
05/21/2007 Reducing the Fire Hazards in Aluminum-Wired Homes, [.pdf document], Jess Aronstein, Ph.D., 21 May 2007. This document answers most technical questions about the hazards and remedies of aluminum electrical wiring and includes
a report on independent test results of alternative products and methods for repairing aluminum wiring. Some of the sections of this very thorough document are listed below:
02/09/2006Reducing the Fire Hazards in Aluminum-Wired Homes, Jess Aronstein, Ph.D., This older version of the above document also answers most technical questions about the hazards and remedies of aluminum electrical wiring
but lacks latest repair product testing such as the AlumiConn connector discussed above. Some of the sections of this very thorough document are listed below:
[UPDATED-DF 03/08/2003, Edits-df 02/09/2006]
Pigtailing using COPALUM - CPSC recommended,
Pigtailing using Scotchlok 3M - superceded by new alternate repair as of June 2007 - a tested, useable aluminum wiring connector method, with a link to step-by-step "how to" photos,
Pigtailing using Ideal 65 - NOT RECOMMENDED, aluminum wiring failures research, field and lab experience, expert sources.
Circuit Breaker, a bad one fails to trip failure at aluminum bus-to-circuit breaker connection - field report and photographs
Electrical Panels, How to Inspect in buildings, safety for electrical inspectors, electrical panel, fusing, wiring defects, defective products. Inspection Class Presentation
Mobile View
The Aluminum Wiring Information Website 
Carson Dunlop's Home Inspector's Home Study Course