Using 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, 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
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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.
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.
A Guide to 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.].
A Guide to Use of 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]
A Guide to Use of 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."
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 devicves 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 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.
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 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.
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.
Guide to Use of 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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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
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 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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