Those who decide to build a house face a difficult task. It’s difficult to act as a general contractor for other people, but when you decide to build your own house, as my parents did in the early 1970s, it’s even more difficult. A million decisions are to be made in an information-scarce and rapidly changing environment, and a wrong step can actually put you in a permanent mess. Coupled with the budget that my people have to work hard on, it is a miracle that they can be as successful as before.
However, this is still close in several places. I still remember my father was troubled by the wiring of the house. Aluminum wire is much cheaper, while the price of copper wire has skyrocketed recently. He gritted his teeth and asked an electrician to install the copper, which was ultimately a wise choice, because houses that had succumbed to the sirens of cheap wiring would soon burn down across the United States.
In the late 1960s and early 1970s, what happened in the residential and commercial electrical industries was expensive and in some cases was a tragic lesson in failed projects. Let’s see how this happened.
To understand the fiasco of aluminum wiring, one must keep in mind not only material science and electrical engineering issues, but also the market forces that made aluminum wiring in residential buildings so attractive at the time. By the early 1960s, worldwide copper production had been high, but voluntary production restrictions to reduce oversupply increased prices. At about the same time, the escalation of the Vietnam War and the prosperity of the housing construction industry increased the demand for copper, while the nationalization of the copper industry by overseas producers and the strikes of miners restricted supply. Squeezed at both ends of the supply and demand equation, the price of copper almost tripled between 1962 and 1964.
Copper wire has long been the standard for residential and commercial branch circuit wiring, and the wiring distance from the load center to the lights and sockets around the structure has been long. Electricians know copper very well and have written electrical regulations around its performance characteristics, and equipment manufacturers have designed switches, sockets and connectors specifically for copper wires. However, due to copper’s deep roots, price increases began to turn copper wires into antimony, and power contractors began to feel the bottom line tightening. Some must be paid.
Enter aluminum. Aluminum is an excellent conductor of electricity-neglecting precious metals, aluminum ranks after copper on the conductivity chart. Aluminum has been used for electrical wiring for a long time, but it is mainly used by utility companies for overhead wiring in power distribution systems. Aluminum’s light weight and low cost are huge benefits. Aluminum has also been used in residential buildings, mainly for service drip irrigation from utility poles to electric meters to load centers. However, while aluminum is common in clothes dryers and higher amperage branch circuit wiring, it is not used in the lighter branch circuits that make up the bulk of house wiring. Everything will change.
In response to the copper crisis, wire manufacturers began to produce aluminum wires for 15 A and 20 A branch circuits. This circuit is usually wired with 14 AWG and 12 AWG copper wires, respectively. However, as good as aluminum, its conductivity is still only about 60% of copper. Therefore, the aluminum wire of the branch circuit needs to be upgraded to the next AWG size. The 15 A circuit is 12 AWG, and the 20 A circuit is 10 AWG. Manufacturers have to use more metal, but aluminum is so much cheaper that it makes economic sense. As a result, aluminum wires began to enter the residential branch circuit, reaching 2 million houses between 1965 and 1972.
This decision will be counterproductive for two reasons. The first is the aluminum alloy chosen by the manufacturer for the wire. The utility wire uses an alloy called AA-1350. Although AA-1350 is very suitable for use in overhead and underground power distribution systems, it is essential pure aluminum with some trace metals added, and its physical properties are significantly different from copper. Due to its high thermal expansion coefficient, AA-1350 aluminum exhibits significant creep, deforming when the metal wire expands and contracts due to heating.
The creep of the electrical connection can be severe. As more current flows, any conductor heats up, but due to its higher expansion coefficient, aluminum expands more than copper. Expanding and shrinking wires may actually loosen the terminals, which loosens the wires and causes arcing, which can lead to more heat and more creep, until eventually a fire source is formed in the house walls.
Improper installation can also increase creep, which often happens as electricians switch from copper to aluminum. Aluminum is much softer than copper, so it is difficult to obtain proper screw terminal torque. Aluminum also rapidly oxidizes when exposed to air, forming a thin insulating layer that can increase the resistance of the connection. Aluminum wire should be treated with preservative before termination, but very rarely. Moreover, manufacturers of sockets and switches have been slow to adjust their products to meet aluminum demand, resulting in unreliable connections becoming more prone to creep.
Finally, basic chemistry seems to have been ignored. Recall that as long as dissimilar metals touch each other, an electric current effect will occur. What is needed to cause corrosion is a small amount of electrolyte, such as condensing water vapor in hot air and penetrating into cold outer walls and wiring. Corroded connections are high-resistance connections with predictable results.
As the aluminum wire house started to burn, firefighters and insurance adjusters couldn’t help but notice the problem, and the days of using AA-1350 house wiring ended. By 1972, the electrical industry had directly modified aluminum wiring from the revised electrical specifications, which stipulated new formulas for aluminum wiring dimensions, and then turned to equipment manufacturers, who changed their products to make them compatible with aluminum wires. Wire manufacturers also changed their products, designing new alloys in the AA-8000 series, mixing iron into the mixture to reduce creep trends.
However, none of these can save aluminum in the branch circuit. By the mid-1970s, most of the branch circuits in the new structure no longer used aluminum, but it hadn’t been before damage. The installation base of aluminum wiring is huge, and houses of that era were subject to strict inspections by house inspectors when they changed owners. The fiasco of aluminum wires has spawned a variety of products to reduce risk, from extremely expensive connectors to special crimps that cold weld aluminum wires to copper pigtails. It is also an option to completely remove the aluminum branch circuit wiring and replace it with copper, although this is expensive and destructive.
When market forces conflict with engineering best practices, the industry’s attempts at aluminum proved to be an expensive lesson.
The problem here is not that the wiring is cheap. It’s just that people don’t know how to use it safely. Obviously, this is not a drop in copper wiring alternatives.
There is another problem with the AL wire. Heat and moisture caused it to be damaged. I lost the main ground wire and dropped to 2 strands, and the rest was dust. This will cause the hot wires to cross, causing the voltage to jump to 200V, which indicates that my led bulb is dimming/brightening.
I put a 100A sub-panel at home, and the electrician I consulted told me to use Al because it costs about 1/10. In other words, if it is installed correctly, there is no danger. In any case, the wires entering the house from the street are all 95% Al, and it has not caught fire! The trick is proper torque, rated connectors and no oxygen.
After 6 years, I will check my connection every year, and I have checked the ESA without any problems. If done correctly, there is no danger. The problem in the past was pure copper switches connected to aluminum wires, etc.
Yes, if the operation is correct, the aluminum wire is safe. Part of the problem with the Al branch circuit is that homeowners often change switches and sockets without knowing the correct technology, or connect lighting fixtures to wire nuts.
As a homeowner, I can prove it. My house has metal cladding to go to the metal box. There are insulated black and white inside the MC, and exposed aluminum conductors. If terminated correctly, this is not a problem. The MC is actually the ground. Before inserting the aluminum into the accessory, the aluminum must be cut off or bent backwards on the outside of the MC. However, in a few boxes, previous homeowners have connected aluminum to the ground screw on the socket, and even copper wire nuts in the box with multiple sockets. This behavior does not worry me (I have solved all the problems now), but it proves the point of view that I will do anything when facing strangers.
I did this at the insistence of the inspector. This is not true, but it is usually not a problem, because when it works loosely, it usually does not move enough to touch any moving objects. I prefer to use metal with a ground plane (green insulated ground wire in the US). The armor still needs to be glued, but for aluminum armor, the use of special copper wires can usually make the ground more reliable (yes, this statement can be justified: copper resistors are usually kept at the installed value, while cast aluminum Steel armored accessories, Al classification and accessories in aluminum boxes usually increase over time, even without liquid water. The armor still needs to be grounded at both ends. It needs to be on the existing circuit before installing a new machine Do a ground test, and the failure exceeds the limit? You bet it is.)
It is not moving and touching something. It is about to loosen in the connector, oxidize and become a high resistance connection, which heats up and eventually melts the aluminum core. Oxidized aluminum is aluminum oxide with a relatively high melting temperature, but internally unoxidized aluminum has a much lower melting point. This will cause your connection to collapse from the inside and cause the connection to become looser.
For the ground connection, it has no current for a long time (hopefully), so heating is no longer a problem. In order to keep the grounding connector connected, the grounding resistance only needs to be lower than yours and provide a good enough connection to flow enough current to trip the load’s circuit breaker.
The metal cladding is not the ground. aluminum. The ground wire is a ground wire and bend back as you describe to ground the MC armor. The spiral aluminum tube will be oxidized like other aluminum, and in extreme cases may cause ground current to flow through the entire length of the spiral. This may be enough to prevent the circuit breaker from tripping, while at the same time acting as a heating element, it is likely to be buried in the insulating layer of indeterminate life and flammability. aluminum. There is a ground wire to provide a low resistance path to ground to prevent this from happening.
If your ground connection has thermal expansion problems, something is wrong-unless there is a fault, the ground will never see current. I am not familiar with NEC’s requirements for Al grounding. Reasons, but I will be at a loss, guessing they need to be specifically listed for Al. The UL mechanism.
Sometimes, electrical wiring equipment may need to list UL tests in a white paper that meets NEC wiring requirements. Most modern sockets and switch terminals are UL certified and can only be used for copper wire connections. The aluminum wire must be twisted copper wire in order to connect to any commercial or residential grade outlets and switchgear. Unless the AHJ approval agency accepts a special configuration, the manufacturer states that it usually meets the requirements listed by UL. R. Benton Jacks
One problem is that most switches and sockets are designed for 14 or 12 gauge wires, and inserting larger Al wires into them may cause poor connections or damage the wires.
Your electrician is correct. It is completely normal to use aluminum as a feeder, because aluminum is usually not bothered by home gamers. If they are properly prepared using deoxygenating compounds and tightened to the correct specifications, there is no problem. When people change sockets and switches, they improperly take care of aluminum. This is the beginning of the problem. In addition, many fixtures also include copper wires that thread the nut to the branch circuit. If you connect copper and aluminum, it will oxidize and generate heat. For feeders, it is difficult to purchase copper in large sizes, and if possible, copper will quickly become expensive. Power companies use aluminum feeders as a cost control consideration, and in outdoor and underground connections, the connection methods are different and the heat generation is small.
It uses it for a bunch of 15-20 amp branch circuits, mixes it with existing copper wires, and so on, which can cause real problems.
This. Aluminum is a standard specification rated material of hundreds or thousands of amperes in many modern applications under the United States and other specifications. It’s just not most small branch circuits. Overhead three-phase transmission lines that you see on the road or as part of a large transmission line? aluminum. Lighter and cheaper. Especially at higher voltages.
“It turns out that when market forces conflict with engineering best practices, the industry’s attempts at aluminum are an expensive lesson.”
More like: when design changes are made without sufficient prior testing. I think this is an engineering best practice in itself, but if the push for aluminum wiring is handled by a more thorough engineering process management, it will work well (see the conclusion of AA-8000) and will be better than copper Wiring is cheap. Therefore, if expensive and feasible is the “best practice”, then cheap and feasible must be the “best project”.
All aspects of engineering (electrical, mechanical, aviation, software, etc.) follow the same basic rules and are usually ignored. When changing system components, you need to recertify the system, not just the components.
@p In other words, the changes to the system (electrical, mechanical, aviation, software, etc.) are smarter than the engineer who designed it. (not necessarily)
Not necessarily smart, but he must fully understand all the original design parameters, including luck. That rarely happens.
Interestingly, this article on the abuse of aluminum is on the same page as the article starting with Ayn Rand’s quote without sufficient prior experimentation. I found myself rewriting the first part of the dialogue between James and Dagne Taggart, and then put down Atlas Shrugged. This gave James a more reasonable reason. He was against Dagne’s order for 1,000 miles of railway inventory. Any aluminum alloy tested outside the lab, and no discrete testing for several miles in the past year or so.
“Any damn fool can build a bridge strong enough to drive over. Engineers need to build a bridge “just” strong enough to cross.”
View. But please compare the earlier VCR with the later VCR. Generally, the materials used are less and different. For example, metal plastics are used. The design is “enough” to use, if not durable.
There is aluminum wire in my house because it was built in the 50s. Therefore, the purchase price of my house was reduced from the appraiser’s asking price. I have spent hours adding aluminum or ideal twisted connectors to ensure that my house will not burn. This is a practical problem that still exists today, especially because there are thousands of old houses there. Connectors are expensive, but insurance costs are also expensive. You must disclose this type of item because it is a fire hazard.
This article explains this problem well. Compared with copper, aluminum has a greater coefficient of expansion. As old equipment ages, screws and terminals will loosen, and the risk of using Al will be higher. I have many stories about elevators not working due to loose terminals. In the long run, are short-term cost savings worth the risk? I think it depends on how often you check the equipment and whether you are willing to reduce the value of the house.
I still remember reading that aluminum cannot bend like copper. This is a problem that the socket will move slightly when plugging or unplugging.
^This. As a scraper, I noticed that aluminum wires are increasingly used in cheap household appliances, such as microwave ovens. In theory, the internal wires will not bend too much, but I don’t buy them.
Are you sure that there is no stranded tinned copper? I do know that some microwave oven transformers use AL magnet wire for the primary winding, but it’s no big deal. Its coil is coated with varnish and then welded in two places. There is not much to go wrong.
Yes, I am sure. Copper is like scraper gold, so we have to check it. Yes, many microwaves also have aluminum wiring in transformers. Kinda ruined the fun of scrapping them…
You will see a lot of aluminum in cheap transformers and motors. The problem is that they varnish it like copper wire, it is really difficult to tell if the varnish is not scratched.
As long as you understand the characteristics of aluminum, there is nothing wrong with using aluminum wire in any items including household appliances. Aluminum wiring can even be used for house wiring and is now understood by people. The last socket I looked closely was marked with AL/CU (aluminum and copper ratings), which told me they had figured out how to make the point of failure (screw terminal) safe.
Reduce the cost of evaluation, won’t it save you property tax every year? If you can save installation costs and convince yourself, you can do well enough to ensure safety, which seems to be a win-win for me.
Not in most parts of the United States. The tax assessment is based on the formula (land area, structure and size, structural features that can be occupied (such as the number and size of bedrooms, the number and size of bathrooms, other rooms, windows and functions) (skylights add approximately to my tax assessment $1000)) The completed basement, fixtures, such as laundry sinks, etc.), at best, are related to market value to some extent. My tax assessment is more than twice my market value. The assessment is adjusted based on the house price (registered by block in my area), depending on the location of the property. If you are too far from the market, in theory, you can appeal. In my area, unless the formula is wrong or the rate is found to be incorrect, appeals rarely work.
Generally, the type of wiring, the paint on the feet, and for that matter, termites and holes in the floor do not affect the tax assessment.
The insurance rate is closely related to the market/replacement value and risk assessment, including the distance from the fire plug, the type of wire, the age and condition of electrical use, the age and condition of gas use, structural considerations and termite damage, paint Flakes and holes in the floor (all these holes have lower values, but increase the risk, so you need to pay more to reduce protection).
I have an older house and I want to upgrade its service from 60A to 200A. Everything must be updated to meet current regulations. Since there was no ground wire, I finally spent 3 years removing and replacing all wires. After completion, each room has its own dedicated circuit breaker, instead of using 7 fuses to power the entire 5 bedrooms/2 bathrooms.
When I removed the base of the old meter, I also found that the wire sheath showed signs of melting. Two four-fuse boxes are placed side by side and bridged together with split nuts. It was found that two of the circuits were connected together, so pulling out a fuse did not power off the branch (hard to find). There are many other little sins, too many. I don’t know why that house was never burned down.
What a timely article. I just bought a house with an aluminum branch circuit (yes, intentionally). This summer, I will embark on a full copper refurbishment, panel movement and garage sub-panel. This is a considerable task, but I can do most of the work myself, so I can afford it.
Any data that can cause a fire when using a “rear wiring” socket? I own two houses, and their main connection method is push-in back-side wire connection instead of screws. I found that many houses are malfunctioning or showing carbonization.
Like the aluminum wire, changes have been made to correct early problems. That said, I still don’t use back stabs (spring contact back line method) because they still fail for many reasons.
I did use several types of back wires with fixed screw clamps (insert the wires through the guide holes and tighten the screws instead of hooking the wire ends)
I like the new captive screw, which is the old “push and hope” type I encountered.
I have replaced a bunch of push-in sockets that are getting hotter. I don’t care what anyone says, I don’t use them. This is not the case when high-quality sockets cost more than two dollars.
The type with fixing screw + clamp may be more reliable than the wire under the screw type. The fixture is actually a rigid copper alloy spring, so it will not creep with temperature cycling. Since the 1960s, this has been the standard configuration of industrial screw terminals.
I remember when they first came out. I doubt it, but I still used a backstab. Hey, this is a UL listed product. By chance, I remodeled a kitchen for a friend who bought a house that I wired up 20 years ago. This is the house where I used the backstab method. When I took out the socket or switch to rework certain circuits, the socket/switch would actually fall apart. High resistance, obvious thermal damage. What surprised me was that the connectors used today replaced nuts.
My clothes dryer stops working intermittently. Therefore, I checked all the connections in the dryer. No luck. Occasionally, my (brand new) home had a problem with the wiring of the dryer socket, so I opened it.
Backstab? Incomplete. The wiring person thinks this is a backstab, even though it is actually a backstab that requires screws to be tightened. My new house was burned down.
Did the electrician make a mistake? Not too possible. The contractor probably hired a friend of a plumber to do the wiring.
Can they even make a back-stab connection of around 50A anywhere? Not sure about your country/region (and voltage and amperage), but usually if you are a US user, the current connected to your dryer is 40A or higher. I have never seen one of them or even a later Thorny.
Given the description of the other party, they refer to all-electric clothes dryers. No matter who runs the 540 V circuit, it is impossible to tighten the screws used to secure the conductors
Negative! It is a 240-volt connector, which may be 50 amps, but I don’t think so now. The connector is not back-stab-style, but the “plumber’s nightmare” that puts it together, obviously. Strange, because the rest of the house is 20A, with proper side wires, using screws like an honest electrician.
My current project is to repair electric fences, for which I paid to install insulators. They did it wrong and could not withstand the wire tension that pulled them. Please wait, this is not the current project. This is a potential project. Well I think I mean a VOLTAGE project.
In the United States, the range is usually 50A. Because this requires the use of stranded conductors, it is difficult to push it into option C. All electric clothes dryers are usually 30A. It can be fed with solid conductors, but I have never encountered a push option there.
Yes, six stores in my store closed last year. It turns out that no matter who is connected to the socket, the back stab of other daisy-chained GFCI sockets is used. I went to work with the burnt outlet to show to my great man.
These devices can still be used. Obviously, a large number of sample surveys in the insurance industry have not revealed widespread problems. When those very small data sets want to show that they exist, they have not yet reached this level. The insurance industry exists to make money. Regarding the specifications they recommend, they will not tolerate losses, nor will they be too strict to be able to afford the cost of constructing buildings.
“They won’t have such strict restrictions that they can’t afford to build buildings.” Yes. Trump still has the ability to build things.
Insurance companies don’t want to eliminate the fire/risk, because then, people will have no reason to pay insurance money-they never want to make themselves redundant.
The risk must always be high enough to keep the premiums going up, and the way to profit is to deny you coverage due to certain sub-clauses or other 22 clauses.
Devices with push-in connection options have been used for decades. Where they are still available. Most likely it means that the insurance industry has no evidence that they are a common cause of fires. It may be those devices that have been designed and approved to solve certain fire investigation problems discovered.
There must be a problem with the spring-fixed anti-stab device. I can’t tell you how many times I have encountered this problem, but I may be biased by being an electrician. This problem may go undetected because they are unlikely to cause a fire. Usually, it will only cause intermittent problems, or it will disconnect the rest of the circuit.
Another problem I see is that after ten years, if left in place, they can still “work”, but as long as someone (electrician) physically moves the device, it will crash/fail.
Even in a hurry, I will never use a bayonet again, it is better to use a suitable hook/screw method, and it is better to stitch everything together into a braid. Even though the device provides a screw with straight/back-stab option, which can mechanically clamp the conductor, I still try to use hooks and screws.
I don’t think the UK uses aluminum for home wiring, but British Telecom is trying to use it for twisted pair wiring. A similar disaster followed. Although fire is not an inevitable problem of communication, once it is corroded, it is a disaster.
Aluminum is also fine. A few years ago, I purchased a length of flat four-circuit, single-conductor telephone cable for indoor use. To my surprise, although the conductor emits a red light after the insulation is stripped, it is magnetic (attracted and lifted by the magnet)! So I went to another place and bought myself another cable…that was the same…copper-plated iron wire (I think it was).
For reference only, the U.S. Army field telephone line is composed of copper and steel stranded wire. This steel provides strength to the wire, and the fingers of field telephone experts pierced many needles.
Do not. It is a mix of strength (steel) and conductivity (copper). We also use this finger-friendly cable in the military. On the voice frequency, you can ignore the skin effect. By the way, I use this wire as a dipole antenna: D, because it is really strong…
Magnetic wire has obvious skin effect at sound frequencies. It is actually a non-conductor above 300 Hz.
Aluminum wiring still makes BT feel a headache. I heard that about 20% of the twisted pair cables installed in some places are aluminum…
In the late 1970s after the aluminum industry ended, I was a practicing electrician. A lot of aluminum was still installed at that time. The worst installation I have seen was that the builder spliced ​​aluminum into copper before entering the electrical box and after the main panel. The house was built in 1972. We were asked to solve some weird electrical problems. When I found the work done and told the homeowner about the total cost of rewiring, he said “no thanks” and we left. As far as I know, this house is still standing, and wit has not been replaced.
Lol i won’t succeed liar. I will not consider using AL for most of CU’s work and charge a fee.
It was in 1977. Depending on when and where the house was built, I assumed a major diver found a way to dump the remaining aluminum wire. This is in western New York. Unless the prosecutor is involved in the transaction, I don’t understand how the thick wire passes the inspection. I was wiring when I was 77, and local inspectors always check for rough wiring before the rock formation rises. The wire is actually crimped together with the 4-wire crimp. We use it for the permanent connection about 4 inches outside of all electrical boxes, except for the wiring between the panel and the first box.
If my memory is correct, then the whole disaster is the cause of Giraldo Rivera’s insult. I mean, it made him famous in the press. Drawing a map on the sand disappointed him.
“Although removing the aluminum branch wiring and replacing it with copper is also an option, although it is expensive and destructive.”
There is nothing worse than upgrading the entire house from insufficient and old wiring* to something that can meet modern needs.
I often encounter old insulated wires (before World War II). Are the insulating materials used at that time organic materials and cloth? -Crash over time.
The worst thing! We call it ragwire, and it has metal coiled armor. The best way is to replace it, but if you cannot be very careful. I usually put a plastic sleeve where the wires extend from the armor, just in case, electrical tape is also necessary. Just look at it will cause a short circuit!
The old wires you mentioned are cloth-covered rubber insulated wires. As long as the insulation is still in good condition, there is no problem with the wires. After World War II, cloth sheathed rubber insulated wires were also used. Modern THHN wires are insulated by nylon-coated polyvinyl chloride, and the polyvinyl chloride in modern wires will also be damaged over time. Depending on the application, armored cables are still used today. You will see it wherever wiring must be exposed, because Romex house wires should only be inside the wall, except for the very short bare wire, which is the ultimate jump from the wall to the water heater.
As you mentioned, “as long as the insulating material is still in good condition” is the key. Even if it is kept in a climate-controlled space, it is rare. Curious if asbestos has been used in residential wire insulation applications?
It must be… The rubber is so dry that it breaks the insulating layer into powder with a hammer. And I’m pretty sure this is before the war. The house where the cable came out was built in the 1920s.
I have also encountered leaded cables from the same period. I understand that this is used outdoors and underground.
@Shannon I sometimes find that a lead-coated cable has two twisted copper cores, an insulating layer and a top layer.
Shannon: HTTP: //lmgtfy.com/ Q = Lead + Cover + Electricity + Cable & NUM = 20 & newwindow = 1 & RLZ = 1C1CHFX_enUS611US611 & TBM = isch & source = IU & ictx = 1 & fir = uwBoo4uTG6tCmM% 253A% 252Cq_bTOM 252CQ_bTOM_CmM% 253A% 252Cq_bTOM_CmM% 253A% 252CQ_bTOM 252CQ_bTOM_CmM% 253A% 252CQ_bTOM %V CmM% X&VED = 0ahUKEwitn6z30fbaAhXN21MKHYwIBMwQ9QEIUTAI #imgrc = uwBoo4uTG6tCmM:
There is insulation between the copper conductor and the lead sheath (the same idea as laying wires inside a metal conduit).
Our house was built in the 50s. A previous owner used romex to rewire the house, but never redone the doorbell. Needless to say, it will never run well. We finished the operation of installing the ring and punched holes in the wall panel of the restaurant to supply power through the plug-in transformer. It’s a bit ugly, but it works, and there is a cabinet in front of the mess. We asked the electrician how much it would cost to go through the attic from the actual transformer in the attic to the front door, and laughed.
You mean something with “chocolate” insulation. It has the structural properties of stale chocolate. Something wonderful. / s Over time, copper hardens and becomes brittle, almost as bad.
The farmhouse I grew up more than 200 years ago had knobs and pipes in the attic. It looks like bare copper wires with only a few inches between the insulators of the electric fence posts. Once or twice a year, I have to go there and remove the dead rat carcass from the wire and replace the fuse again.
When I was a child, my grandparents had wiring for knobs and pipes in the house. Run the lighting with the ZIP cable fixed on the wall, and turn the lighting switch 1/4 turn to the right to turn on/off/on/off the lighting. The entire house is protected by a fuse at the end of the attic where the cable enters the house. Unless you are the unfortunate field mouse and decide to step on the wrong two lines and then say “po, no mouse”, this is very safe.
There is a knob or two buried somewhere in the house. Reuse most of the electricity (old and new).
I actually like knobs and tubes. The conductors are physically separated and cross the insulators. it’s not a big deal. What is a bear, is integrating it with modern unified wiring.
I once filmed a documentary about Bach, and some churches in the former East Germany also used aluminum wire, ending the Mecano style with a metal fuse box. Brrr…
The electrician is here. I once worked as a service electrician in a company. I received a call and someone complained that the socket was glowing. I am bragging because I have received all kinds of crazy calls (ie IE; old analog TV is monitoring me). Sure enough, if you look at the sockets, several of them will actually glow red when there is a proper load on the circuit like a space heater. The lady said this has happened for many years! This is aluminum wiring, which leads to high resistance connections due to oxide/creep.
It happened for many years! Gosh, I saw the glowing wires and immediately turned off the power. The sockets and walls must also be burnt.
“Although removing the aluminum branch wiring and replacing it with copper is also an option, although it is expensive and destructive.”
Do American houses not use PVC conduit for wiring? If so, then replacing the branch wiring is actually not that difficult or destructive.​​​​
Disconnect the power to the affected circuit and confirm that the wires are not charged, connect the pull spring/cable to the wires in the junction box, and then use the old cable to pull the other end of the cable out of the cable. Connect the new wire to the traction cable. Insert the new wire into the conduit, reconnect the device and power on.
Tear off the gypsum board and put it all back in place, including all the time and labor-intensive work required, including packing the gypsum board and repainting all the paint, even then it doesn’t look right. This is an absurd way of building. You can’t even view it, let alone change or upgrade it.
Reminds me of the post a few days ago, that person basically cut dozens of drywall rectangles just to put some wires on his closet server. Makes you afraid of the time required to repair.
EMT (or thicker) would be fine, but then (seems) no one would buy a house because of “ugliness”. Fortunately, catheters can be used in commercial and industrial applications, people actually care about maintenance, and the design of the structure cannot last for 20 or 30 years.
You can bury the EMT on the wall. Some cities, such as Chicago, need it. I like to use these things, especially in renovations, but it lacks flexibility and is therefore limited.
Now you know why so many people do most of their work through the attic or second-best crawl space or basement. One benefit of tearing off the plasterboard is that if you have to re-insulate it first, then (foaming is not bad, but it still has holes)
Non-metallic sheathed cables have been used in residential buildings in most parts of the United States for decades. The code requires it to be nailed near the device box. Usually, channels are found in houses in orderly cities where transactions are not normal. I am a laborer and an auxiliary laborer, but I am not out of date. I do a good job and comply with legal requirements. That’s just disturbing your customers.
> PVC conduit? If so, then replacing the branch wiring is actually not that difficult or destructive.​​​​
Hehehe… PVC pipe has been used in the wall for 30 years, please try to pull anything through it-the pipe will break into pieces. Oh, well, it’s time to tear off the plasterboard.
A few months ago, I had replaced part of the wiring in my house (built in the mid-80s), no matter what the pipe broke. I have never even heard that this is a problem.
At the same time, all this is going on, and stainless steel is used to replace copper water pipes. The result is intergranular corrosion and pinhole leakage.
Many leads have now been replaced. However, as long as the water chemistry (* ahem * Flint) is properly maintained, lead-water pipelines will not cause problems, just like aluminum wires.
Then, “not a problem anymore”. Likewise, as long as the chemical properties of water are properly maintained.
Even with the wattage, you can always tell the effect of mixing two metals. A small (solid-state) radio consumes less than half an ampere at 115v (a quarter of 230v), but at 12v ? The shit will turn black, green, and then sticky!
A viscous component is a heat insulation grade that is not suitable for exposure to a combination of the following factors: heat, copper corrosion and alumina. When trying to peel and twist the “twisted” connection again, it does not work, uC will continue to crash/drop
There are still some oak water pipes in the city where I went to college. It was built in the 1800s. They erupt once every ten years or so. It turns out they can be replaced. The only difference is that today they have stainless steel bands (external) instead of lead.
The old band is iron. Lead is not strong enough. It is used for the service line from the main body to the house. When we were doing sewer works in southern Tacoma, we pulled out some abandoned 54-inch wooden wall lines. It is still in good condition. I believe that there are still miles of old 54-inch wires exposed on the concrete supports to supply Tacoma with water.
Aluminum or copper: Poor circuit overload. The circuit breaker can’t stop stupid, just hope it can slow it down, and nothing is maintenance-free.
I have seen quite a few modern cheap cables, they are aluminized aluminum. The problem is that it looks like copper, currently mainly in network cables, but there are also some twisted ultra-flex cables around it. Isn’t that good? Even if you just power on the quadcopter. Has anyone noticed that the power cables or IEC power cables on appliances are too light? Are they aluminum?
The biggest problem with aluminum is that it does not see use cases when it is refurbished and mixed with other more common electrical components. They did not assume that people would use copper jumpers and wire nuts in aluminum wires, and they might add aluminum wires to the old copper wire system. Why this happens is a mystery to me, because any electrician with a power company will know from experience what problems can cause. This is a huge failure of NFPA (Electrical Code).
All of these are before I received the training, we learned the code used for the AL branch circuit at that time, and accepted the remedy. Has the NFPA approved the practice used by the municipality or the failure of the municipality? The municipality can choose to adopt or not adopt NEC, or modify the advertisement.
For high-speed internet connections, this may make sense. The skin effect of high frequency will cause the signal to propagate on the cable surface. In a high power setting, this won’t work because copper is much more conductive than aluminum, so that most of the current will avoid the center of the cable, and your effective cross section will become that of copper. For flexible power cords, aluminum is not a particularly good choice, because for the same current carrying capacity, aluminum must be larger. The conductivity of aluminum is only about 60% of copper.
Watch out for CCA! The Chinese sell cheap “copper-clad aluminum” in smaller low-voltage meters. This is absolutely nonsense and will soon corrode. It is usually listed as “copper” on Amazon, eBay, and other sites in the main description, but when you look at the beautiful words, it will display “CCA”. As the price of copper soars again, the price of this scrap is usually less than half of copper.
I made a huge mistake, which was to use it for 12V LED decorative lighting installation outdoors, not far from the beach. Despite the fact that everything was welded and not directly exposed to rain or salty air in the shell, it corroded in less than 4 months. I used more equipment in indoor installations closer to the beach, and it even corroded within 18 months. I ended up having to rewire these two projects from scratch, and the cost was high.
Worse is the CCA Ethernet cable. Guaranteed to not work properly. https://www.cablinginstall.com/articles/2011/03/ccca-cda-warn-against-copper-clad-aluminum-cables.html
I will not contradict the experts, but I am surprised that, considering the skin effect, for high frequency applications, clad conductors do not work well.
I think this requires a minimum thickness of cladding, which may not be in the best interest of Chinese suppliers.
Some electrical upgrades were made to the sockets of the contractor of the townhouse. The thick AL thick aluminum stranded wire is hardly suitable for installation on the wall. There is no chance to bend it. Tie to the copper with the correct knot and anti-c band. One of the worst things I have ever done. In theory, replacing the container in SoSF Ca requires a permit and inspection. They use industry-wide inspectors who know nothing here, including simple division of departments or 1000/160. “Oh…give me four roof vents.” He has nothing. I have used ridge ventilation. I also saw my first lead pipe in SF Victorian era (after Clue). Perfect P-trap in perfect shape. Replace it. The Roto Router I used here said: “You need to cut your hair short. Otherwise you can’t do it. It’s too difficult.” I paid him 300 to 150. Still can’t solve it. There is no refund. I hate fools. Want everything profitable.
I work in a cable company. We use all-copper-clad steel and triple-shielded aluminum foil (aluminum foil woven aluminum foil), while the satellite company uses pure copper conductors during operation. Due to the skin effect, we only need to coat copper. I have not seen the aluminum center conductor, a lot of nonsense cables, but there is no aluminum.
When using AL, increasing the line voltage is not a solution to basic corrosion problems. Not to mention compatibility with all devices currently in use or in the supply stream. Global climate change will lead to a deadlock in hell, after which the United States will use higher voltages to illuminate the circuits of small household appliances. Please shut down before our current POTUS allows you to pay for the change.
With LED lighting, we really no longer need 15A lighting circuits. We can use the 18v specification 120v 5A for lighting applications. One circuit can still light up the entire house.
We actually only need 15A or 20A plugs to be used for heating equipment, such as space heaters, toasters, kettles, etc… as well as refrigeration, refrigerators, freezers and air conditioners.
Unless copper becomes very expensive, change will never happen. Then I can see other solutions, such as smart power. The plugged-in device talks to the inverter, and the inverter supplies power with the required voltage up to 600v. Therefore, your 1000W toaster will require 600V and therefore only consume 1.6A current, which may exceed the 20 gauge line. Unplug the toaster and put your fingers in, it may only be 30V. As long as the equipment needs it, the voltage will only increase. Every circuit must be a home run, which may offset any cost savings of smaller wires.
Hush! If people start doing maths like this, the only place we can run power tools in a new house is the kitchen! Is that what you want? ! ? That may be the death of an amateur. The only people who build anything for generations from now are the people who work.
We will never see 600V in a residence. Insulation requirements and working gaps have become too cumbersome to be implemented safely and economically. As you suggested, smart circuits will also be too expensive for device circuits. Each circuit needs to feed exactly one device. If this is not the case, the device will need to proxy a common voltage, and then each circuit will be limited by the voltage limit of the device with the weakest voltage rating, and the current carrying capacity of the wiring needs to be set to handle the total current of all devices on the circuit The lowest voltage is the large gauge wire.
If each circuit has its own multi-kilowatt smart buck-boost AC converter, what do we really gain besides adding additional cost load? Is it possible to move the oven from one wall to another? Your dryer goes from the laundry room to the bedroom? Your compressor goes from the garage to the recreation room? Yes, these examples are absurd in design, enough to show that most of the flexibility gained at a huge cost is useless to homeowners. Except for a few exceptions (such as hair dryers, electric kettles, microwave ovens, toasters, turkey frying pans, power tools), the location of sockets for high-power users can be accurately predicted during construction or reconstruction, and the circuit is designed to be the lowest Provide power safely at a cost. In addition to the high cost of high-power smart AC converters, if we stipulate that heavy users account for 85% of electricity bills and the efficiency of these smart converters is 97%, we will also increase electricity bills by 2.63%. Not very green.
I can see some common sense improvements in our future. Low-voltage smart circuits will be the way to safety. A group of 1-n LED bulbs can communicate with the upstream smart circuit breaker-if the circuit breaker cannot explain each mA current passing through it, it can declare a fault condition, trigger the bulb self-test to isolate the faulty device, if it is determined that all devices are If it is normal and the wiring is wrong, it will trip or trip. We can do the same for low-voltage and low-power devices such as phone chargers, toys, and other wall warts.
I would like to see Smart Power Report* Panel GFCI circuit breakers with reasonable prices. I can buy a 20A 120V GFCI socket for around US$15, while a 20A 120V GFCI panel circuit breaker costs US$40. The bipolar 240V version is about twice the latter. 50A 240V panel GFCI pushes the price of 100 dollars. Security must be affordable. I want to view power consumption circuit by circuit in order to make smart power consumption decisions.
Are there sparks in the UK willing to contribute to aluminum wiring? I have moved a lot of equipment in a 3-phase industrial park in the UK, and I have never touched aluminum wires. Have you never seen anything here in a home environment?
The house builder also used plastic pipes to connect the external public water supply system to the house, which failed in the early 1990s (see the big blueprint), and the polybutene pipes inside the house were also used for distribution. Unable to withstand water hammer, this also damaged the inner wall due to the pipe rupture.
Lesson: You have to pay for everything the market will bear, not the price based on the quality of the house. If the builder can make choices that save money, his profit margin will increase. You are not saving the price. Therefore, strict building codes and inspections are required.
Decades later, the clarinet from the meter to the house is still strong. PEX survived the recent winter very smoothly.
I like my copper cold water pipe, it can be used as a ground connection. I have never failed with copper pipes… and sweat-welded pipes…a piece of cake!
I know some people dare not try to solder copper pipes, but as far as I know, the only people who really encounter difficulties are those who insist on cutting corners, missing flux or removing oxidation.
The combination of aluminum wire and FPE or Zinsco panels…this is the root of the disaster! The wiring is on fire and the circuit breaker does not trip!
The reality is that they may all fail. Recently I had a 277/480 20A Square D QO bolt in the circuit breaker that failed to trip. During a commercial demonstration, I accidentally cut the live 12/2 AC cable on the 277V lighting circuit (yes, this is the best of us). Apart from blowing up the pliers, I was surprised to watch the arc start to melt the cable. It’s like some kind of slow firework fuse. Run to the electrical cabinet 200 feet away from the closet, basically by listening to the “buzz” to find the correct panel, and then by running my back to isolate the circuit breaker in order to find a hot/hot circuit breaker . To my surprise, Square D is reliable in the electrical industry and is widely praised. The panel was installed in the mid-1980s and may not have undergone any preventive maintenance since it was opened.
Sometimes overcurrent protection is too sensitive. Years ago, I basically made the same mistake as above (I can say that nonsense will happen when an electrician is more than 25 years old). This is also the 20A 277V lighting circuit. It hardly made any traces of my pliers, nor did it trip the 20A circuit breaker. On the contrary, it took all 26 floors of the office building! The ground fault setting of the main switchgear is incorrect. Can’t believe they have never encountered this problem before.
My parents’ house has aluminum wire. I freaked out it! For thicker wires, you must put the compound adhesive there. it. It sucks when I change the ventilator and switch in their house, I always wrap the outside with electrical tape (I actually use tape in my house), and I very carefully tighten the terminal screws . No changes will be made there. But the house has stood for more than forty years.
All branch circuits are great. Whenever I receive a service call to replace the socket and pull out the old socket and find all the problems, I cringe. The backstab is great. Good friends don’t let friends back stab-but it keeps the service call open. Several renovations were made to the entire house. If the house uses flexible conduit for wiring, it will take several days of work. It does not flexibly complete four left-right operations on the up, down, left, and right access. Entry is never a problem-good electricians carry saw blades with them
The screw does not turn. What happens is that the aluminum heats up, expands and presses on the screw, leaving a dent. When the wire cools, it shrinks and leaves a gap. The gap allows oxygen to corrode the aluminum, thereby increasing electrical resistance, which causes the wire to heat up the next time the same load is applied. Repeat this process until it catches fire or the wire melts or the contact is insufficient to conduct electricity. A common observation is that the wire is loose and turning the screw will stop the movement, but this does not mean that the screw will turn to cause the connector to loosen.
My own experience – I have a supplier who uses aluminum in a similar application and told me that Locktite is malfunctioning and allows the fastener to be unscrewed, but the fastener does not turn easily. The deformation of aluminum parts is only greater than the pre-tightening force of the screws.
The amount of deformation required for relaxation is approximately 0.005 inches. There may be more investors who propose the expected elastic preload, but I think the screw is a fine thread, so each revolution is about 0.030 inches. I don’t remember that the time between full contact and full austerity is less than a quarter.
You have determined the exact reason for the failure. Due to thermal expansion and contraction, the aluminum wire will loosen over time. Copper will also expand and contract, but not as far as aluminum, plus brass screws will expand and contract with wires.
The solution to this problem may be to add a simple washer under the screw to increase some length, because a longer screw will increase the spring force.
The same problem applies where the sheet metal is connected with screws. Washers are usually avoided because they add more interfaces and these interfaces will slip, but for thin materials, since the elastic force of the screw along its axis is proportional to the free length of the screw, thermal expansion tends to loosen the joint.
I have a 1979 Oldmobile Cutlass Supreme, and its battery was stolen by some despicable people. They use wire cutters to cut the battery cables instead of unscrewing the terminals. When I got into the car in the morning, I discovered this and saw that the door lock was hung outside the door through some kind of linkage, and the hood was slightly opened. To say that I was shocked emotionally.
To my surprise, judging from the exposed cross section of the battery cable, the wire harness has copper on the outside, but the center of each wire is silver aluminum. I saw it for the first time. I hope all copper.
I tried to solder the acid core of the new cable to the old cable with a propane torch, but the solder just liquefied and fell to the ground. I ended up with a clip that clamped the old wire to the new wire and wrapped it with tape. It worked for several years, until I sold the car.
Missed two points (after so many comments!)-Aluminum is more prone to fatigue when it is stretched and bent into place, which leads to higher resistance points and therefore becomes a hot spot-For similar reasons, Telecom (Australia’s existing telecommunications company Now called Telstra) aluminum is used for telephone cables in some places. It doesn’t matter, until ADSL is completely messed up by the connection between Al and Cu. In some parts of towns, such as Dubbo, people cannot get DSL without extensive rewiring, and this is almost immediately replaced by NBN fiber.
Even utility companies can and do have a lot to do with the correct installation of aluminum wiring. After a heavy rain (thunder and lightning, heavy rain), our house began to experience strange electrical problems, such as LED ceiling lamps fried and electrical deaths when “turned on”. I turned off the main power disconnect switch and all circuit breakers in the load center of my home, turned on the main power, and tested the voltage on one leg of 120V, when I turned, the voltage on both legs rose from ~121V to the other 78V on the other, 158V on more circuit breakers. Florida Power and Light installed underground wiring from the utility pole to the meter, and neglected to put any insulating grease on the underground connection at the bottom of the utility pole. Nearly 40 years later, the neutral connection was almost aluminum oxide powder surrounded by aluminum powder. The remaining AL cables were partially oxidized. At least we saved one of the two neighbors connected to the same pole-they have always had the problem of flickering lights, and the shared neutral connection blocks of all three houses are too hot for repair technology to handle (due to corrosion -> Heat!!!)
Aluminum is more ductile than copper, so the possibility of a finer gauge wire being pulled or crushed is thinner or easier to bundle than copper. Any wire whose thickness is changed beyond the design purpose will fail due to the changed resistance. Thin wires will reduce resistance and overheating; thick wires will increase resistance and short circuits.
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