Do we have to Repair the Ground Wire When Making Aluminum Wiring Repairs using Pigtailing? InspectAPedia® -
Why the ground wire should be included when performing aluminum wiring repairs
How to make space in electrical boxes to fit copper pigtails and connectors on aluminum wiring
Choice of connectors for repairing aluminum ground wire connections
How to reduce the risks associated with aluminum electrical wiring
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This article describes the importance of including repair of the grounding conductor (ground wire) in buildings where where solid conductor aluminum electrical wiring is being repaired. 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 for proper repair methods, and see MAKING SPACE FOR ALUMINUM WIRE CONNECTORS if you are having trouble fitting the repair connectors and wires into the existing electrical boxes. Our photo (at page top) shows an attempted aluminum wiring repair using a twist-on connector - not a recommended method. You can see that the aluminum ground wire was left unchanged. Also see ELECTRICAL GROUND SYSTEM INSPECTION where we describe problems with bare aluminum ground wires in buildings.
Do We Need to Pigtail the Ground Wire When Reducing the Hazard of Aluminum Electrical Wiring?
A reader faced with limited space in the electrical boxes of his building asked if it was acceptable to just pigtail the current carrying conductors - the "hot" and "neutral" wires, leaving the aluminum ground wire alone. Our photo (left) shows an improper aluminum wiring repair - the white twist-on connector is not recommended for this application. Thanks to Dr. Jess Aronstein for clarifying this question with the comments below.
The electrical ground is part of the electrical safety system and must be capable of carrying current under various fault and malfunction conditions. The probability of any wire termination or splice of a ground conductor actually carrying substantial current is low relative to the circuit conductors (line and neutral), but not low enough that it can be ignored. That is why modern codes require full-size ground conductors.
Questions regarding electrical code issues are best answered by your local electrical inspection authority, since applicable interpretations vary. In the long run, you should use what is presently listed for the application or what the local electrical inspection authority and your insurer will sign off on.
Because the reader was considering using twist on connectors where the recommended aluminum wiring repair connectors may not fit (not a procedure that we recommend) we strongly advised that he employ the special procedure (wire abrasion under a film of inhibitor, and pre twisting) as described at Reducing the Fire Hazards in Aluminum Wired Homes.
In the financial analysis of the cost of performing a complete and proper repair of aluminum electrical wiring, be sure to include consideration of the possibility that a repair considered to be permanent (CPSC --COPALUM) could have some long-term payback through the value that it adds to the property.
Detailed Advice for Aluminum Ground Wire Connections during Aluminum Wire Repair in buildings
Is it necessary to use a rated "pigtail" connector, such as the Alumiconn or COPALUM connectors, on the grounding circuit given that the ground only carries current if and when a fault occurs? It would save considerable money, and space in the fixture box, to use those rated connectors only on the hot and neutral wires which regularly carry current.
The question of how to handle the grounding conductor in aluminum wired homes arises from time to time, especially because in some installations of crowded wiring in junction boxes, people want to leave out the ground pigtail connection. Dr. Jess Aronstein, expert on aluminum wiring failures, testing, and repair procedures, in discussing this topic, has noted that:
The ground is part of the electrical safety system and must be capable of carrying current under various fault and malfunction conditions. The probability of any wire termination or splice of a ground conductor actually carrying substantial current is low relative to the circuit conductors (line and neutral), but not low enough that it can be ignored. That is why modern codes require full-size ground conductors.
The questions regarding code issues are best answered by your local electrical inspection authority, since applicable interpretations vary. In the long run, you should use what is presently listed for the application or what the local electrical inspection authority and your insurer will sign off on.
It must permit the repair of every connection to, or splice between, aluminum wire in the home;
The repaired connections must be permanent but must result in a system that can be maintained without the need for special switches, wall outlets or other connectors;
The repair technique must be practical for use in an occupied and furnished home.
Can I Use Twist-on Connectors for Aluminum Ground Wires?
If you do use any twist-on connectors (we and the US CPSC specifically do not recommend this approach, including we do not recommend use of the Ideal-65 "twister" purple twist on connector sold for aluminum wiring repair), we strongly advise that you employ the special procedure (wire abrasion under a film of inhibitor, and pretwisting) as introduced at http://www.inspectapedia.com/aluminum/alreduce.htm and described in more detail in the report "Reducing the Fire hazard...." found at http://www.inspectapedia.com/aluminum/alreduce.pdf
In the financial analysis of the cost of aluminum wiring repair for large buildings, it is important to consider the possibility that a repair considered to be permanent (COPALUM or the Alumiconn) could have some long-term payback through the value that it adds to the property.
Best Practices Guide to Repairing Aluminum Ground Wire Connections
All aluminum wire conductors should be repaired, including the aluminum ground wire.
Since the electrical ground wire is not normally carrying current it may be that aluminum ground wire connections might be in better shape and at lower risk of failure than other wires in an AL wired circuit. BUT
One of the mechanisms that leads to poor aluminum ground wire connections is mechanical or other disturbances of the electrical device such as an electrical receptacle or switch or fixture. Even though it is not normally conducting current, the ground wire connection at the device is also subject to deterioration from these other forces.
Since at the very time that a ground wire is going to be called-on to conduct current is an emergency, it seems to me foolish to leave that wire in any doubt whatsoever.
Two Connectors Recommended for Repairing Aluminum Wiring, including Ground Wiring
The AMP/TYCO COPALUM crimp connector repair consists of attaching a piece of copper wire to the existing aluminum wire branch circuit with a specially designed metal sleeve and powered crimping tool. The metal sleeve is called a COPALUM parallel splice connector and is manufactured only by AMP Incorporated. This special connector can be properly installed only with the matching AMP tool. This tool makes a permanent connection that is, in effect, a cold weld. An insulating sleeve is placed around the crimp connector to complete the repair.
The CPSC-sponsored research, laboratory tests, and demonstration projects identified only one method of repairing existing aluminum wire circuits which meet these criteria. That repair is known as the crimp connector repair. But that CPSC publication was written before the AlumiConn was listed - the AlumiConn connector is also an acceptable repair. (just to be clear)
How Can we Address the Problem of Limited Space in the Electrical Junction Box?
Two comments about the space problem inside the junction box:
NEC has made an exception to standard cu. in. space requirements per number of conductors to make it a little easier for an AL wire repair to meet code
When we had a space problem in junction boxes at a rewiring job we purchased box extenders - some suppliers call them "sidecars" that allowed me to extend the size of each metal junction box in the building by removing the exposed side plate of the box and screwing on the extender that gave a few more cu. in. of working space to push wires back into the box. This might mean cutting and patching drywall wherever this was needed at receptacles and switches.
At an actual 4" square junction box there are also box extenders that increase the total box depth - but that fix means loosening and then re-securing the box so that its face remains flush if it's showing in an interior space. In an attic or basement or other unfinished it should be possible to extend the box sizes without the cosmetic repair issue.
Another approach could be thinner (front to back) receptacles. They do vary a bit from brand to brand and model to model.
Space taken up by aluminum wiring repair connectors
The Alumiconn (recommended) is not much different from the Ideal #65 twist on connector (not recommended) in the volume that it takes up, provided that the wires are bent appropriately.
Just tighten the existing aluminum ground wire connections?
A general worry is that whenever we do any repair on a building safety topic that is less than the recommended or optimum procedures, the risk picture is foggy - people think that the issue has been "fixed" so they forget about it - which can lead to someone ignoring danger signals and later having a problem.
What About Other Aluminum Wire "repair" Products such as CO/ALR devices?
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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
Thanks to reader Thomas Kremer for suggesting clarification to this topic 08/09
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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
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The Aluminum Wiring Information Website 
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