UL's View Of Aluminum Electrical Components
I have mentioned this clearly several times in several threads, now I will scream it.
NO MATTER WHAT BRAND OF RV YOU HAVE YOU
MUST MUST MUST MUST
REMOVE THE COVER OFF OF THE ALTERNATING SHORE POWER CURRENT BREAKER BOX AFTER SEVERAL HUNDRED HOURS AND RE TIGHTEN EVERY SINGLE SET SCREW IN THE BOX.
Every single last RV, motorhome, trailer, campe, camp trailer. If it has a breaker box, then it has aluminum bars inside with set screws. And the screws WILL LOOSEN UP. Cause wire and even the rig to burn up.
Read what an insurance underwriter, one of the folks that UNDERWRITE UL the Underwriter's Laboratory had to say about aluminum. Down the column a ways it talks about this very issue.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
and
Events
Aluminum
Wiring
Hazard
Mitigation
-
April
2012
The event: a fire at the Beverly Hills Supper Club in Southgate, Kentucky on the night of May 28, 1977. The fire killed 165 people and injured more than 200 people -- making it the third-deadliest nightclub fire in U.S. history. The cause: an aluminum wire electrical system -- the factor cited often in causing building fires.
Risks of Aluminum Wire Electrical Systems
Aluminum wire, normally found in residential building structures -- apartments, condominiums, and private homes -- fails typically in electrical connections that are 15 amps and 20 amps (#12 gage and #10 gage). Aluminum wire installed between 1965 and 1971 is most likely to be "old technology" wire (AA-1350) and that installed from 1972 to 1975 could be either "old technology" wire or "new technology" wire (AA-8000). Even after the discontinued use of aluminum wire, contractors were allowed to use existing stock -- and residential buildings built as late as 1975 could contain "old technology" aluminum wire.
The "old technology" aluminum wire was more subject to failure than copper wire because of:
Creep -- a measure of the rate of change in gradual deformation as the result of stress. Aluminum wire has a higher creep rate than copper wire.
Cold Flow -- related to creep but a permanent deformation as the result of momentary stress. Cold flow does not vary over time.
High Expansion Coefficient -- expansion while under heat stress. Aluminum wire has a higher coefficient of expansion than copper wire.
Corrosion (Oxidation) -- formation of oxides causing high electrical resistance. Often cited as a contributing cause of failure at aluminum connections.
Brittleness -- aluminum wire does not have the strength and flexibility of copper wire.
These are all physical features of aluminum wire that can create loose electrical connections that can lead to electrical arcing and can generate enough heat and sparks to ignite combustible material.
The "new technology" aluminum wire was an attempt by the aluminum industry to correct some of the product's failure characteristics. The aluminum wire installed in 1972 and after has lower cold flow and brittleness than what was produced prior to 1972. However, these failure characteristics were not totally eliminated and the problems with high-expansion coefficient and oxidation remain.
Reducing the Risks of Aluminum Wire Electrical Systems
The methods available for reducing an aluminum wire fire hazard:
Re-wire the building replacing all aluminum branch circuit wiring with copper. This is considered the best but most expensive repair method for aluminum wiring.
COPALUM Crimp Connector is the attaching of a piece of copper wire to the existing aluminum wire with a specially designed metal sleeve and crimping tool. The crimping tool uses a full-compression crimp method to make what is, essentially, a cold weld that results in a permanent connection. There is no major disadvantage in this method as it may be used for most every type of electrical connection and it is considered a permanent repair. Only distributors authorized by the manufacturer (AMP, Inc.) has the crimp tool available for rental. Rental privileges are granted only to electricians that have completed a training program.
"Pig-tailing" is the disconnecting of the aluminum wire, joining it to a short length of copper wire and using an aluminum/copper-type wire connector. The major disadvantage of this method is that some brands of the twist-on wire connectors have been known to overheat. This method is one of the least effective in reducing the fire hazard because the failure-prone aluminum/copper connection is not eliminated -- only moved from a terminal to a splice.
CO/ALR (pronounced "CO-LAR") Devices are receptacles and switches designed to be compatible with aluminum wire (only available in 15 amp and 20 amp ratings). The major disadvantage of this method is that it is limited to only receptacles and switches -- which do not include ceiling-mounted fixtures, permanently wired appliances, dimmer switches and ground fault circuit interrupters (GFCI). Also, the device manufacturers recommend annually removing the receptacles and switches and testing the terminals for tightness. If this maintenance is not completed, the manufacturer’s specific instructions are violated. This method is also one of the least effective in reducing the fire hazard because of the incomplete and impermanent repair.
The recommended solution to aluminum branch circuit wiring, besides a complete re-wire or the COPALUM crimp connector method (the only two solutions recommended by the Consumer Product Safety Commission), is:
Note: Twist-on connectors (i.e., wire nuts), whether Listed or not, are not recommended because of their questionable performance history and specific installation techniques.
Recommended Solutions for Aluminum Wire Installations
Old Technology (AA-1350)
Outlets & Switches: CO/ALR
Fixtures, Appliances, & Junctions*: (High) pressure crimp method.** Terminal Connectors (e.g. set-screw lugs).
Sub-Panel: Listed Breakers (i.e. AL-CU).
Maintenance: Annual infrared survey or annual physical inspection including torque/tighten and clean.
New Technology (AA-8000)
Outlets & Switches: CO/ALR
Fixtures, Appliances, & Junctions*: Per NEC (i.e. methods using products Listed for aluminum).
Sub-Panel: Listed Breakers (i.e. AL-CU).
Maintenance: As required by authority having jurisdiction.
*All components must be UL Listed for use with aluminum connectors.
**COPALUM only currently known method.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Tomorrow morning, I have to go out and REPAIR DAMAGE to a 2014 trailer that was caused by this. This is stupid unneeded, expensive, ignorant hassle. The RV industry REFUSES TO ACKNOWLEDGE the issue. A simple DECAL PASTED ON THE BREAKER BOX
WARNING! RE-TIGHTENING TERMINALS INSIDE BY AN AUTHORIZED TECHNICIAN IS REQUIRED ANNUALLY.
Grrrrrrrrrrrrr!
Addendum
Aluminium-Copper: A problematic connection
Generally aluminium is a reactive material that oxidizes easily, but in practice it has proved to offer good corrosion resistance. This characteristic is due to a chemical reaction that takes place when in contact with atmospheric oxygen resulting in a very thin but also very resistant oxide layer being formed. (oxide barrier)
When metals are connected to those with a higher electrical potential such as copper in the presences of an electrolyte (condensed water) will result in an electrochemical reaction taking place. During this process the differences caused in electrochemical potential can have a significant impact.
An electrical circuit is generated by the copper electrode (anode), the electrolyte (water) and the aluminium electrode (cathode). The voltage generated in this copper and aluminium circuit “semi metallic” state results in a short circuit.
As a result of the current generated the Aluminium surface breaks down causing the metal to electrolytically decompose. This destructive process is visible as a kind of blooming oxidation and begins already with the existence of tiny copper particles on the aluminium; this ongoing reaction itself does not cause the copper to corrode. In an electrical connection however the resistance is increased leading to increased temperatures which then in the worst case lead to a fire.
Therefore when connecting copper and aluminium it is important to ensure that no moisture can enter the connections. In an environment where moisture is present the contact points between the copper and aluminium need to be protected by using accurate operating procedures. (see picture 2). Primarily this requires the use of aluminium/ copper cable lugs and connectors. Due to the design of these lugs areas where moisture could accumulate and where the oxidation process could start have been avoided. For this reason aluminium/copper cable lugs and connectors are specified for the use in off-shore wind power stations.
(Source Reference)
http://www.klauke.com/en/electrical/technical-reports/accurately-connecting-copper-and-aluminium/
NO MATTER WHAT BRAND OF RV YOU HAVE YOU
MUST MUST MUST MUST
REMOVE THE COVER OFF OF THE ALTERNATING SHORE POWER CURRENT BREAKER BOX AFTER SEVERAL HUNDRED HOURS AND RE TIGHTEN EVERY SINGLE SET SCREW IN THE BOX.
Every single last RV, motorhome, trailer, campe, camp trailer. If it has a breaker box, then it has aluminum bars inside with set screws. And the screws WILL LOOSEN UP. Cause wire and even the rig to burn up.
Read what an insurance underwriter, one of the folks that UNDERWRITE UL the Underwriter's Laboratory had to say about aluminum. Down the column a ways it talks about this very issue.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
and
Events
Aluminum
Wiring
Hazard
Mitigation
-
April
2012
The event: a fire at the Beverly Hills Supper Club in Southgate, Kentucky on the night of May 28, 1977. The fire killed 165 people and injured more than 200 people -- making it the third-deadliest nightclub fire in U.S. history. The cause: an aluminum wire electrical system -- the factor cited often in causing building fires.
Risks of Aluminum Wire Electrical Systems
Aluminum wire, normally found in residential building structures -- apartments, condominiums, and private homes -- fails typically in electrical connections that are 15 amps and 20 amps (#12 gage and #10 gage). Aluminum wire installed between 1965 and 1971 is most likely to be "old technology" wire (AA-1350) and that installed from 1972 to 1975 could be either "old technology" wire or "new technology" wire (AA-8000). Even after the discontinued use of aluminum wire, contractors were allowed to use existing stock -- and residential buildings built as late as 1975 could contain "old technology" aluminum wire.
The "old technology" aluminum wire was more subject to failure than copper wire because of:
Creep -- a measure of the rate of change in gradual deformation as the result of stress. Aluminum wire has a higher creep rate than copper wire.
Cold Flow -- related to creep but a permanent deformation as the result of momentary stress. Cold flow does not vary over time.
High Expansion Coefficient -- expansion while under heat stress. Aluminum wire has a higher coefficient of expansion than copper wire.
Corrosion (Oxidation) -- formation of oxides causing high electrical resistance. Often cited as a contributing cause of failure at aluminum connections.
Brittleness -- aluminum wire does not have the strength and flexibility of copper wire.
These are all physical features of aluminum wire that can create loose electrical connections that can lead to electrical arcing and can generate enough heat and sparks to ignite combustible material.
The "new technology" aluminum wire was an attempt by the aluminum industry to correct some of the product's failure characteristics. The aluminum wire installed in 1972 and after has lower cold flow and brittleness than what was produced prior to 1972. However, these failure characteristics were not totally eliminated and the problems with high-expansion coefficient and oxidation remain.
Reducing the Risks of Aluminum Wire Electrical Systems
The methods available for reducing an aluminum wire fire hazard:
Re-wire the building replacing all aluminum branch circuit wiring with copper. This is considered the best but most expensive repair method for aluminum wiring.
COPALUM Crimp Connector is the attaching of a piece of copper wire to the existing aluminum wire with a specially designed metal sleeve and crimping tool. The crimping tool uses a full-compression crimp method to make what is, essentially, a cold weld that results in a permanent connection. There is no major disadvantage in this method as it may be used for most every type of electrical connection and it is considered a permanent repair. Only distributors authorized by the manufacturer (AMP, Inc.) has the crimp tool available for rental. Rental privileges are granted only to electricians that have completed a training program.
"Pig-tailing" is the disconnecting of the aluminum wire, joining it to a short length of copper wire and using an aluminum/copper-type wire connector. The major disadvantage of this method is that some brands of the twist-on wire connectors have been known to overheat. This method is one of the least effective in reducing the fire hazard because the failure-prone aluminum/copper connection is not eliminated -- only moved from a terminal to a splice.
CO/ALR (pronounced "CO-LAR") Devices are receptacles and switches designed to be compatible with aluminum wire (only available in 15 amp and 20 amp ratings). The major disadvantage of this method is that it is limited to only receptacles and switches -- which do not include ceiling-mounted fixtures, permanently wired appliances, dimmer switches and ground fault circuit interrupters (GFCI). Also, the device manufacturers recommend annually removing the receptacles and switches and testing the terminals for tightness. If this maintenance is not completed, the manufacturer’s specific instructions are violated. This method is also one of the least effective in reducing the fire hazard because of the incomplete and impermanent repair.
The recommended solution to aluminum branch circuit wiring, besides a complete re-wire or the COPALUM crimp connector method (the only two solutions recommended by the Consumer Product Safety Commission), is:
Note: Twist-on connectors (i.e., wire nuts), whether Listed or not, are not recommended because of their questionable performance history and specific installation techniques.
Recommended Solutions for Aluminum Wire Installations
Old Technology (AA-1350)
Outlets & Switches: CO/ALR
Fixtures, Appliances, & Junctions*: (High) pressure crimp method.** Terminal Connectors (e.g. set-screw lugs).
Sub-Panel: Listed Breakers (i.e. AL-CU).
Maintenance: Annual infrared survey or annual physical inspection including torque/tighten and clean.
New Technology (AA-8000)
Outlets & Switches: CO/ALR
Fixtures, Appliances, & Junctions*: Per NEC (i.e. methods using products Listed for aluminum).
Sub-Panel: Listed Breakers (i.e. AL-CU).
Maintenance: As required by authority having jurisdiction.
*All components must be UL Listed for use with aluminum connectors.
**COPALUM only currently known method.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Tomorrow morning, I have to go out and REPAIR DAMAGE to a 2014 trailer that was caused by this. This is stupid unneeded, expensive, ignorant hassle. The RV industry REFUSES TO ACKNOWLEDGE the issue. A simple DECAL PASTED ON THE BREAKER BOX
WARNING! RE-TIGHTENING TERMINALS INSIDE BY AN AUTHORIZED TECHNICIAN IS REQUIRED ANNUALLY.
Grrrrrrrrrrrrr!
Addendum
Aluminium-Copper: A problematic connection
Generally aluminium is a reactive material that oxidizes easily, but in practice it has proved to offer good corrosion resistance. This characteristic is due to a chemical reaction that takes place when in contact with atmospheric oxygen resulting in a very thin but also very resistant oxide layer being formed. (oxide barrier)
When metals are connected to those with a higher electrical potential such as copper in the presences of an electrolyte (condensed water) will result in an electrochemical reaction taking place. During this process the differences caused in electrochemical potential can have a significant impact.
An electrical circuit is generated by the copper electrode (anode), the electrolyte (water) and the aluminium electrode (cathode). The voltage generated in this copper and aluminium circuit “semi metallic” state results in a short circuit.
As a result of the current generated the Aluminium surface breaks down causing the metal to electrolytically decompose. This destructive process is visible as a kind of blooming oxidation and begins already with the existence of tiny copper particles on the aluminium; this ongoing reaction itself does not cause the copper to corrode. In an electrical connection however the resistance is increased leading to increased temperatures which then in the worst case lead to a fire.
Therefore when connecting copper and aluminium it is important to ensure that no moisture can enter the connections. In an environment where moisture is present the contact points between the copper and aluminium need to be protected by using accurate operating procedures. (see picture 2). Primarily this requires the use of aluminium/ copper cable lugs and connectors. Due to the design of these lugs areas where moisture could accumulate and where the oxidation process could start have been avoided. For this reason aluminium/copper cable lugs and connectors are specified for the use in off-shore wind power stations.
(Source Reference)
http://www.klauke.com/en/electrical/technical-reports/accurately-connecting-copper-and-aluminium/
