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Using COALR or CU-AL Electrical Outlets and Switches with Aluminum Wire ElectricAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

Why we should not use CU-AL or AL-CU -marked electrical outlets, recptacles, or switches as a "repair" for aluminum wiring What are the concerns with COALR or CO/ALR -marked electrical devices when used with aluminum wiring The history, differences in performance, and significance of COALR, CO/ALR, CU-AL and AL-CU -marked electrical devices in aluminum-wired homes Our site 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 inspect-ny.com/appointment.htm. This article explains why COALR, CO/ALR, AL-CU or CU-AL marked devices are not recommended for use with aluminum wiring as a "repair" for aluminum wiring. We explain the differences between COALR, CO/ALR devices and AL-CU or CU-AL devices - they are not equivalent! Aluminum wire connections can overheat enough to start a fire without ever drawing enough current to trip a circuit breaker. Making proper repairs to aluminum electrical wiring, using the proper electrical wire connectors and methods, can bring the level of electrical wiring safety in building to about the same as a copper-wired building. Making improper repairs to aluminum wiring might actually increase the level of risk. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use the links at page left to navigate this document or to go to Other Website Topics. Green links at left show where you are in our document & website.

Use of COALR, CO/ALR, AL-CU or CU-AL Marked Electrical Devices, Switches or Recptacles with Aluminum Wiring

Electrical Receptacles and switches marked COALR, CO/ALR, AL-CU or CU-AL have not been recommended by the US CPSC for aluminum wiring repairs. However COALR or CO/ALR - marked devices are not and should not be treated identically with electrical devices marked CU-AL or AL-CU.

Prior to the introduction of the "CO/ALR" wiring devices in about 1973, UL did not have any standard or standard tests for wiring device terminals for aluminum wire. The markings prior to that time regarding type of wire were optional for the manufacturer to apply as they wished. UL considered all wiring devices with screw terminals as suitable for aluminum wire, even if the devices also had push-in backwired terminals.

The photograph shows a back-wired electrical receptacle with an aluminum-wired branch circuit. In these photos the electrical receptacle was marked as AL-CU but was further marked as Backwire CU-ONLY by its manufacturer. As we report in more detail below, devices marked AL-CU performed poorly when tested with aluminum wire, and backwiring these receptacles increases the risk of an electrical failure. ["Electrical receptacle" as used in our articles is a synonym for "electrical outlet" or what some people call a "wall plug" or "wall socket". "Electrical devices" includes receptacles, switches, and possibly other electrical components which are connected to the electrical wiring in a building.
Technical content courtesy of Dr.Jess Aronstein. Photographs shown above courtesy of Roger Hankey. Other photographs are by Daniel Friedman. Contributions of photos of CU-AL and COALR recptacles are sought by the author.].

Electrical devices marked CU-AL or AL-CU

The CU-AL and AL-CU markings were applied by the wiring device manufacturers at their option, without any special testing for compatability with Aluminum Wire. This was allowed (by UL) until about 1972. Most of the devices marked this way are identical to those (of the same model # "family" from the same manufacturer) that are not marked AL-CU ofr CU-AL.

• The AL-CU or CU-AL marking was a manufacturer's option. Within a brand and model line - Leviton 5320 receptacle, for instance - there was no difference in design or construction (other than the stamped marking) between the devices that were marked "AL-Cu" and those that were not.
• If the electrician and/or jurisdictional electrial or building inspector required the wiring devices to have the markings, they were available with the markings.
• Since the markings were optional with the manufacturer, there was a wide variety, but most commonly either none or "Al-Cu", and, either way, the wiring devices were considered to be, promoted as, and sold as suitable for use with aluminum wire.
• In about 1974 UL published a pamphlet on aluminum wiring which warned that the wiring devices with the "AL-CU" marking should not be used with aluminum wire. [We are looking for a copy of this document - DJF]

Electrical devices marked COALR or CO/ALR

In about 1972, UL and the wiring device manufacturers agreed on a test standard for receptacles for use with Aluminum Wire. The devices that passed the standard were marked CO/ALR.

Five manufacturers initially manufactured "CO/ALR" wiring devices (receptacles and switches), and we believe that one or two continue to manufacture them today.

Since devices marked COALR or CO/ALR conform to the UL standard for compatibility with aluminum wire, the devices with CO/ALR markings must be considered differently - they are not the same as the AL-CU or CU-AL devices.

Summary of Test Results Comparing COALR and CU-AL Electrical Devices

Wright-Malta Corporation conducted long-term tests of "old technology" (including "CU-AL") wiring devices and CO/ALR devices for CPSC.

[Aronstein reports in summary that there were] "... many failures and burnouts of the "old technology" receptacles, and one failure (burnout) of a CO/ALR device."

Should COALR or CO/ALR or CU-AL or AL-CU -Marked Devices Be Used With or as a "Repair" for Aluminum Wiring?

1. Make the proper repair: We recommend that aluminum-wired homes be repaired using only one of the approved, recommended measures described at HOW TO REDUCE THE RISK of aluminum electrical wiring in buildings
2. CU-AL or AL-CU marked electrical outlets, switches, or other devices should not be used as a repair for aluminum electrical wiring.
3. COALR or CO/ALR marked electrical devices as tested by Wright Malta Corporation performed better than CU-AL devices when used with aluminum branch circuit wiring provided that the connections and wiring were installed properly. Aronstein has not [yet] commented, for example, on aluminum wiring and back-wired receptacles with COALR devicves nor on field reports of aluminum wiring failures with either type of marked electrical device.
   
   The replacement of receptacles with CO/ALR devices is treated to some extent in the report "Reducing The Fire Hazard in Aluminum-Wired Homes" a document available at this website. [If/when that topic is expanded we will provide notice of the update at this page and website.]
   
   One might reasonably infer that it may be the case that an aluminum-wired home which has properly installed, not-backwired COALR or CO/ALR electrical outlets and switches might be at a lower risk level of an incident than homes without these devices, and such a home is probably at lower risk of an electrical incident than homes wired with CU-AL or AL-CU marked devics. But risk assessment of the condition of aluminum wiring in any individual building is more complex than just this. Relying on the observation of the presence of COALR devices alone to assess risk is questionable at best.
4. Don't guess about aluminum wire safety: We recommend against guessing about the condition of aluminum wiring in a building or making any assumption about its safety if the wiring has not been repaired using an approved method. We also recommend against relying on superficial and possibly technically un-sound safety surveys using test instruments in buildings as a way to assess the risk of aluminum electrical wiring and as a way to decide whether or not to repair it.
5. The level of risk in an aluminum-wired building: Assessing the actual level of risk associated with aluminum wiring at any individual building is difficult, highly technical, requires special equipment and procedures, and should not simply be "guessed" based on casual observations like "no problems have been reported" or "we have COALR devices already installed" or "the workmanship here was good".
   
   The risk of an overheating connection in an aluminum-wired building varies with many factors which are difficult to assess because many of the variables are simply not visible, and because any individual risk assessment, even using special equipment, cannot predict future changes in building conditions, changes that could occur moments after the assessor left these building.
   
   Some of these variables include changes in use of an electrical circut by a new occupant, changes in the condition of an electrical connection, say at a receptacle, as the device is used, increased deterioration of an individual electrical connection in a building with age or time, variations in electrical installation workmanship from one part of a building to another. We have received mail from readers reporting that a home inspector or electrician has "looked at the wiring" and has proclaimed it "safe". Such assessments are nonsense, irresponsible, and are potentially dangerous.
6. The US CPSC has recommended only re-wiring or use of the AMP TYCO COPALUM connector and the "copper pigtailing" repair approach for aluminum wiring, and that there is one additional newer product, the AlumiConn, which appears to perform well in this application, readers should note that no authority has recommended use of electrical switches or outlets of any kind as a "repair" method for aluminum wiring

Examples of Improperly-Wired COALR or AL-CU Devices with Aluminum Wiring

These photographs from a large condominium complex wired with aluminum show aluminum wiring connected to an electrical outlet marked CU-ONLY.

• This aluminum-wired device was not installed according to the manufacturer's specifications. The receptacle manufacturer marked it as CU-Only (right photo) and it is wired with aluminum wire (left photo). This is an improper electrical installation and it's a safety hazard. Some of the occupants among our clients at this property wanted to simply replace the electrical outlets and switches with COALR or worse, AL-CU devices. As we explain here, installing COALR or CU-Al receptacles on aluminum wiring is not a recommended repair.
• What about all of the other electrical connections and splices in the building?. Even if these devices worked, which has not been demonstrated, I am concerned that any incomplete "repair" of aluminum wiring also risks creating a false sense of security among the building's occupants, possibly leading them to ignore dangerous warning signs of a problem or leading them to fail to complete the proper repair using approved, recommended methods and devices -- OPINION DJF.

Back-wiring Electrical Receptacles with Aluminum Wiring

Back-wiring any electrical receptacle that uses a simple spring-clip to contact the wire internally gives a poor and unreliable connection. In the photograph shown here the electrical receptacle was back-wired with aluminum wire, which is an even less reliable connection. In this photo the little aluminum white jumper wire on the side terminals of this receptacle were added because the copper tab that originally joined those two connectors has been broken off. This suggests that this electrical outlet may have been re-used from a prior installation and raises an additional worry about back-wired receptacles.

Tests of back-wired receptacle connectors conducted by Aronstein indicated that the re-use of a previously back-wired electrical outlet might involve extra risk of the back-wired connector failure, particularly if the receptacle were changed from use with a #12 wire to a #14 wire but possibly in any case since repeated use of the back-wired spring connector tends to weaken the spring and reduce the spring contact pressure on the electrical wire. A loose or questionable connection with aluminum wire increases the chance of an overheating condition at that connection.

In R. Hankey's photos at the top of this page the electrical receptacle was back-wired with aluminum wire specifically in contradiction to the instructions of that particular manufacturer. That installation is an improper and unsafe electrical connection.

Some newer electrical receptacles use a screw-operated clamping connector that pinches the wire in a clamping contact. These may perform more reliably than the older spring-type back-wired connectors when used with copper wire or a copper pigtail connected to aluminum wire by an approved connector.

Other newer electrical receptacles have been re-designed so that the holes on the back of the receptacle are reduced in diameter to now accept only #14 electrical wire, which we'd expect therefore to be only copper and which would exclude use of back-wired aluminum wire connections on these devices. (The smallest gauge residential branch circuit solid conductor wire for a 15-amp circuit would be #12-gauge wire if it were in aluminum or #14-gauge wire if it were copper.) -- OPINION DJF

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More Reading

• 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.
• HOW TO REDUCE THE RISK of aluminum electrical wiring in buildings
• REPAIR ELECTRICIANS specializing in aluminum wiring repairs
• OTHER REPAIR PRODUCTS for aluminum wiring, ones that work, or don't
• DETAILED EXPLANATION of the aluminum electrical wiring hazard

Technical Reviewers

Particular thanks are due to experts and also consumers who read these articles and suggest corrections, changes, and additions to the material. Content suggestions, technical corrections and content critique are invited for any of the content at our website.

• Daniel Friedman - principal editor, is the author of ElectricAPedia ^© and other topics at the InspectAPedia ^© Website
• Dr. Jess Aronstein, Poughkeepsie, NY, - principal technical consultant. Dr. Aronstein is a Consulting Engineer, Mechanical & Materials Engineering, BME, MSME, Ph.D., N.Y.S. P.E. LIC. NO. 39860 845-462-6452 protune@aol.com. He has conducted and continues to conduct extensive testing of electrical devices and connections and works as a forensic engineering consultant.
• Hankey and Brown home inspectors, Eden Prairie, MN, technical review by Roger Hankey, prior chairman, Standards Committee, American Society of Home Inspectors - ASHI. 952 829-0044 - hankeyandbrown.com
• Critique, contributions wanted: Contact Us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

Contents -- More expert information on Aluminum Wiring

Use links 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.

More Information on Aluminum Wiring Hazards and Other Building Diagnostic Inspections and Repairs

• The Aluminum Wiring Information Website Aluminum Wiring Hazards and Repairs: in-depth info, photos, documents. Main Page.
• The Aluminum Electrical Wiring Hazard Explained (in the document you are presently viewing)
• 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)
• Other Products, Ideal 65 Purple Twister (not recommended), & other Aluminum Wire Products/Articles (in the document you are presently viewing)
• The Aluminum Wiring Bibliography: extensive resources on Aluminum Wiring
• Aluminum Wire Failure Reports & Photos: Real life aluminum wiring field failure reports
• Reducing the Fire Hazards in Aluminum-Wired Homes, Jess Aronstein, Ph.D., This document answers most technical questions about the hazards and remedies of aluminum electrical wiring. Some of the sections of this very thorough document are listed below:
• Fire Hazards With Aluminum to Copper Twist-on Connectors & Acceptable Aluminum Wiring Repair Practices Color Photos, Current Issues. 9/28/95 CPSC Meeting Minutes
• "Is YOUR Aluminum Wiring Safe?" article discussing safety claims made by some people without looking at the wiring, J. Aronstein, 11/21/95
• "Repairing Aluminum Wiring," U.S. Consumer Product Safety Commission Publication CPSC#516 available online
• * Safety Hazards and Safe Inspection Procedures for Electrical and Home Inspectors at Residential Electric Panels
• Electrical Panels, How to Inspect in Buildings, safety for electrical inspectors, electrical panel, fusing, wiring defects, defective products. Inspection Class Presentation
• Electrical System & Wiring Hazard Inspection, Detection, Cause, Remedy, Prevention - Main Electrical Page
• Directory of Home Inspectors accessible via Internet

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