Using CU-Only, COALR or CU-AL Electrical Outlets and Switches with Aluminum Wire
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Why we should not use CU-AL or AL-CU -marked electrical outlets, receptacles, 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
Questions & answers about using CO/ALR or CU-AL devices (electrical receptacles, "outlets", or switches) with aluminum electrical wiring
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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.
Use of COALR, CO/ALR, AL-CU or CU-AL or CU-Only Marked Electrical Devices, Switches or Receptacles with Aluminum Wiring
Electrical Receptacles and switches marked COALR, CO/ALR, AL-CU or CU-AL or CU-Only (photo above right) 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. Also, devices marked CU-only are intended for use only with copper wire.
Prior to the introduction of the "CO/ALR" wiring devices in about the 1973 timeframe, 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 the case in these photos
the electrical receptacle was marked as "AL-CU" but was further marked as Backwire CU-ONLY by
its manufacturer.
["Electrical receptacle" as used in our articles is a synonym for "electrical outlet" or what some people inaccurately call a "wall plug" or "wall socket".
"Electrical devices" include 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 courtesy of Roger Hankey. Contributions of photos of CU-AL and COALR receptacles 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
compatibility 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 or 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 electrical 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 or so 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.
A total of 1000 receptacles (4000 wire terminations), were tested, including 500 of the CO/ALR (100 of each brand.
All of the testing was done within the ratings for the wire size and receptacle application.
[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."
Electrical devices marked CU-Only
Electrical devices that are stamped CU-Only are intended only for use with copper wiring and should not be used with aluminum electrical wiring.
Should COALR or CO/ALR or CU-AL or AL-CU -Marked Devices Be Used With or as a "Repair" for Aluminum Wiring?
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
CU-AL or AL-CU marked electrical outlets, switches, or other devices should not be used as a repair for
aluminum electrical wiring.
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 devices nor on field reports
of aluminum wiring failures with either type of marked electrical device.
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 devices. 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.
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.
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 circuit 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.
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 and is a safety hazard. Some of the clients
at this property wanted to simply replace the electrical outlets and switches with COALR or AL-CU devices. As we've explained above, that is
not a recommended repair. Beyond the concerns with use of COALR devices with aluminum wiring in a building we note two additional worries:
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 any electrical receptacle that uses a simple spring-clip to contact the wire internally gives
a poor and unreliable connection. In this case the receptacle was (1) back-wired which is a less reliable
connection, and (2) was back-wired with aluminum wire specifically in contradiction to the instructions of the
manufacturer. This is an improper and unsafe electrical connection. Some newer electrical receptacles that permit back-wiring use a connector that pinches
the wire in a screw-tightened contact and may perform better when used with copper wire or a copper pigtail
connected to aluminum wire by an approved connector. -- OPINION DJF
Reader Questions & Comments on Aluminum wire and CO/ALR CU-AL Devices
Question: What switches or receptacles are OK to use with Solid Conductor Aluminum Electrical Wiring?
Are switches and receptacles marked with Solid Core Wire Only suitable for use with Aluminum Wire? - D.C.
Reply: None
A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem with wiring, use of aluminum wire, and with the connectors, pigtails, or other repairs that have been attempted or that are needed.
That said, the short answer to your question is NO.
Here are some things to consider:
Even CO/ALR devices that the manufacturer has stamped as intended for use with AL wire are not suitable according to industry experts and according to research already performed and documented here. See ALUMINUM WIRING REPAIR NOT-Recommended Products.
If your building has solid conductor AL wiring the proper repairs are either re-wire with copper or pigtail with copper using a CPSC recommended connector. See ALUMINUM WIRING, HOW TO REDUCE THE RISK for details.
Watch out: some "approved" aluminum wire to copper wire connectors that the manufacturer has tested as meeting the appropriate standard in fact do not work, melt, catch fire. And there are no connectors currently sold intended for straight aluminum-to-aluminm connections.
Stick with what the CPSC recommends and you'll be ok.
Questions & Answers regarding this article
Questions & answers about using CO/ALR or CU-AL devices (electrical receptacles, "outlets", or switches) with aluminum electrical wiring
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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.
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:
Dr. Jess Aronstein, Poughkeepsie, NY, - principal technical consultant. Dr. Aronstein is a Consulting Engineer, Mechanical amp; 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
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)
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)
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:
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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