Let's fight about aluminum wire!

[Zwy]

Copper is great for boilers and plumbing.
But is sure is expensive to repair.

I have been on SOOOO many boiler jobs where the copper is eaten with holes throughout.

I've been on many jobs to replace an aluminum tube and fin evaporator with a copper tube and fin.

Copper isn't cheap and it isn't for those who don't demand a higher standard.

And copper coils in hvac was ok in the beginning when thick tubing was used, but when epa started requiring efficient standards, coils were just too thin, and they all failed.

Again, I have replaced many aluminum tube and fin evaporators with copper tube and fin. And copper is more efficient than aluminum on heat transfer, thermal conductivity and co efficient. Aluminum holds the edge on emissivity in the higher infrared range.

Don't believe me? Take to 2 plates of exact same dimensions, one aluminum and one copper. Heat both at the same rate in your hand on the end with a torch. Let me know which one you drop first.

I didn't just fall off the turnip truck. It had nothing to do with the EPA, it was due to the cost of copper.

Every mini split I've installed has copper tube and fin. Every heavy duty application that requires longevity has copper tube and fin. Long term aluminum tube and fin evaporators fail. Copper tube and fin can be missing half the aluminum fins, yet it still has good heat transfer. Same goes for condensers.

The only reason one sees aluminum condensers is due to parallel flow in order to cut weight/size and try to gain efficiency with small passages in each tube. This increases the surface contact area of the tube. Parallel flow has it's problems, but is cheap to manufacture. The small passages plug over time leading to decreased heat transfer as refrigerant is not flowing thru the passages.

Aluminum lasts. It is superior to copper in wet environments. It has points of failure, but better than copper when done right.

I call BS, reasons stated above.

It just has to have more surface area to be as efficient with heat transfer.

You are incorrect. Go check your Machinery's Handbook.
.

 

[bolhuijo]

Every mini split I've installed has copper tube and fin. Every heavy duty application that requires longevity has copper tube and fin. Long term aluminum tube and fin evaporators fail. Copper tube and fin can be missing half the aluminum fins, yet it still has good heat transfer. Same goes for condensers.

The only reason one sees aluminum condensers is due to parallel flow in order to cut weight/size and try to gain efficiency with small passages in each tube. This increases the surface contact area of the tube. Parallel flow has it's problems, but is cheap to manufacture. The small passages plug over time leading to decreased heat transfer as refrigerant is not flowing thru the passages.

Toyota's been putting 100% Aluminum micro channel evaps and condensers in their cars for about 20 years now. They stick those things in the front of the car and let 'em collect dirt, rain, bugs, gravel at 70mph for 10 years and they still work. Not sure why they can't catch on in stationary applications.

 

[Zwy]

Toyota's been putting 100% Aluminum micro channel evaps and condensers in their cars for about 20 years now. They stick those things in the front of the car and let 'em collect dirt, rain, bugs, gravel at 70mph for 10 years and they still work. Not sure why they can't catch on in stationary applications.

That is a parallel flow condenser. It is used in automotive applications because it is cheap to manufacture and can have a higher heat exchange in a smaller package due to the micro passages.

I've installed hundreds in retrofit situations where the original copper tube and fin could not condense the refrigerant on a R134a retrofit. There is a place for a parallel flow condenser.

It doesn't change the fact that copper outperforms aluminum when it comes to heat transfer, co efficient and thermal conductivity.

Part of the reason you won't see this type of condenser adopted in stationary is a stationary system is expected to last longer than the average automotive lifespan. Second, the airflow requirements are completely different and the fan operation is much different. Third, stationary frontal area is really unlimited unlike automotive which has space constraints.. Fourth, the purposes of each system are opposite when it comes to heat pumps compared to automotive air conditioning. A heat pump is used for heating and cooling. The automotive air conditioner is used for only air conditioning. Thus the requirements are very different.

If you saw the automotive condenser failures I see in a season with parallel flow condensers, you would agree with me that stationary is best served with copper. Some of the heavy duty stuff like CAT and other heavy off road are starting to use parallel flow. I keep fast moving truck condensers in inventory as these commonly fail or are damaged by road debris and vibration. The anti icing agents used on highways just eats aluminum parallel flow condensers away between the mounts and end caps. The equipment I service lasts way longer than passenger vehicles, thus I see the longer term failures.

Sure, adopt more aluminum parallel flow condensers, it's very good for my business. Easy money........

 

[SWSL]

Aluminum lasts. It is superior to copper in wet environments. It has points of failure, but better than copper when done right.

Looking over this thread trying to justify going with CCA but no, simply due to resistance.

Maybe I can add some nuance about metal en general, not wiring specific. Aluminum is not a stellar performer in our humid salty conditions by the sea. I'm sure boaters could tell you the same. Better than steel but not as lasting as copper. We live by the sea in a tropical zone and it's impressive to see the aluminum here corrode and turn to white dust. For that reason we use copper as a tie wire building and you may be aware that copper is used for roofing nails in certain cases.
In our climate, for general metal usage life is maybe- Steel 1X to fatal corrosion. Galvanized steel and aluminum 2X, Copper and some stainless 4X, Good stainless 10X. Given same thickness.
Again, this is a general comment, not about resistance or wiring. But since the copper tubing came up as a reference. By the way, I suspect that with the coil thing wall thickness may be in that formula. I bet the aluminum that outlasts thin copper is actually thicker. Probably a cost thing.

 

[seneysolar]

Heres the biggest problem with aluminum wire...

 

[Zwy]

Copper is for kings, aluminum is for the peasants.

Anyone look at copper futures lately? It seems there might be a little squeeze taking place on the Comex.

 

[Jeremiah]

Copper and aluminum have different properties and respond differently to how they carry electrical loads. It is just unsafe to clad aluminum with copper pretending you have a solid copper conductor and than use that as a basis for rating it.

Respectfully nobody here is recommending to pretend Aluminum wire that's copper clad is the same as copper so a bit of a strawman there.

Voltage Drop: V= IR
Power Lost: P = I^2 R = V^2/R

I care about power (W) lost in my PV cables as a function of current (I), more than I do voltage drop.
If my panels are generating 1920W, but I’m losing 100W in the run, that is signifcant.
Losing 10W, who cares?

But it's fine to just talk about "voltage drop" since its intrinsically connected to the loss in power. It's just another variable describing the same symptom and the answer when going Aluminum is simply 1 size bigger then none of this power loss happens.

Hi what do you mean by don't do that? Why not? Didn't worry about voltage drop?

It's not the reason I need thicker cable though. Strictly amps. I never cared about 3% drop.

But you won't be as long as you calculated correctly and got the bigger Alu wire...

Great thread title!

Aluminum doesn't seem worth the extra trouble for a small cost savinga, at least for somebody not in the trade. I'm sure I can be done correctly, but for me saving money on wire is not worth the tradeoff of worrying.

This is a 1st world mentality, which I realize many commenting in the thread are North American or in Europe but for those of us in developing countries the price difference absolutely is more than a "ho hum" deal. In addition, it's pretty common to buy copper wire here and told it's 99.9% pure etc. only to find out you got shafted and now have some mystery metal in your house. At lease with the aluminum stuff there is less reason to cheat / lie and the savings are *SUBSTANTIAL*
Just get 1 or 2 gauge larger and save a ton.

In a 1st world economy why not go copper I get it. But I think there are many in my situation who will find it useful to understand that Aluminum is fine and certainly better than mystery copper haha

 

[Jeremiah]

Oh, im in an attic right now working on the hvac in a pre 1920 house, and this stuff is all over the place... id love to see how aluminum wiri g looks in a hundred years...

I'd love to see 104 year old copper

Copper is for kings, aluminum is for the peasants.

Anyone look at copper futures lately? It seems there might be a little squeeze taking place on the Comex.

Silver is for kings,
copper is for peasants
Aluminum is for other peasants

 

[Luk88]

From a European perspective: what's aluminium wire?
On a serious note, it's used on power distribution, but I've never seen any aluminium wire used in residential in any of the EU countries I've been/lived in.

Another European here. My YAKY and YAKXS wiring would like a word...

I use a lot of YAKXS (I never used YAKY, but above 32mm2 bending YAKXS becomes really difficult) for underground lines. Mostly for the lack of voltage drop.

There was time when copper was cheap when it didn't make any sense. Last time I was buying such cable (a couple of years ago) using double the square area in aluminium still was half the cost of copper. If you're buying $300 worth of a cable it does make a difference it's not $600.

Here is how it looks after ~7 years outdoors (in a distribution box).
Aluminum on the left, copper on the right.

 

[Mattb4]

Respectfully nobody here is recommending to pretend Aluminum wire that's copper clad is the same as copper so a bit of a strawman there.

....

I see you speak for the group. However my comment was not a strawman because it was to the point you made later in your post about buying supposedly copper wire (rated as such) only to find it was CCA.

 

[Zwy]

I'd love to see 104 year old copper

I've seen wiring that old. looks fine and intact.

Silver is for kings,

Gold is for kings, silver is for the peasants.

copper is for peasants

Copper wiring and copper plumbing are now for kings.

Aluminum is for other peasants

And those that do not know any better.

 

[Supervstech]

Aluminum is for loads ove 30A, that is provisioned for increased size wiring, NEVER directly connected to major appliances, always routed between breakers and disconnects.
I have never seen aluminum directly connected to appliances.
Outlets and luminary fixtures need copper clad aluminum or pure copper.

All the "aluminum wiring fires" were from outlets and light switches that got loose connections from loads.

I cringe when i come up on houses from the 70s with aluminum wiring to the outlets and switches.
Costs a bundle to remove all fixtures and install the purple splicers.

Less than a burned down house for sure though.

The worst is when the house has a zinsco main panel, run to a federal pacific subpanel, with all aluminum wiring.

 

[Luk88]

I've seen wiring that old. looks fine and intact.

Was it in a vacuum oven

I've seen plenty of tarnished copper wiring. In fact I have this east german machine (from a country that no longer exists) made in 1964 that uses a sort of "mechanical computer" that has 18 large relays and a huge nest of copper wires. It can be "programmed" with use of plastic blocks. It is a sort of pre-CNC CNC if that makes any sense. Every few months when I try to use it I discover. Oh shit, it doesn't stop where it should... or it stops instead of reversing... etc All because of tarnished copper.

 

[Luk88]

Aluminum is for loads ove 30A, that is provisioned for increased size wiring, NEVER directly connected to major appliances, always routed between breakers and disconnects.
I have never seen aluminum directly connected to appliances.
Outlets and luminary fixtures need copper clad aluminum or pure copper.

All the "aluminum wiring fires" were from outlets and light switches that got loose connections from loads.

I cringe when i come up on houses from the 70s with aluminum wiring to the outlets and switches.
Costs a bundle to remove all fixtures and install the purple splicers.

Less than a burned down house for sure though.

The worst is when the house has a zinsco main panel, run to a federal pacific subpanel, with all aluminum wiring.

Were the alloys so much worse? Or are these outlets and switches corroding aluminium wiring because of brass/copper being in contact with it? If the former I'm very interested what is it that makes today's aluminium better. Better purity? I always thought aluminium in the wires is as pure as possible (as opposed to alloys containing magnesium, silicone and copper found elsewhere).

Here, we use aluminium a lot (outside buildings, very heavy gauge wiring) and every electric supply store has special crimp things and even screw blocks one can use to safely connect aluminium and copper wiring. I don't think it is allowed for internal wiring.

 

[upnorthandpersonal]

Here, we use aluminium a lot (outside buildings, very heavy gauge wiring) and every electric supply store has special crimp things and even screw blocks one can use to safely connect aluminium and copper wiring.

I guess Poland is a bit of an exception in Europe then. I've never seen it in Finland, Belgium, etc. except for high voltage power distribution. Never seen it in a domestic setting.

 

[Luk88]

I guess Poland is a bit of an exception in Europe then. I've never seen it in Finland, Belgium, etc. except for high voltage power distribution. Never seen it in a domestic setting.

It depends what do you consider domestic. Your typical person living in a flat, or a house with or without builtin garage will never see it.

Even my house's main connection is copper(it is considered better, if you're building a house spending $100k+, what is extra few hundred $). However, once you start having multiple buildings on site 40m plus apart, each needing 5kW+ per phase and very intolerant to voltage drop (3ph welders etc), that's where this kind of cabling is used.

So I bet most people in my country have never seen this kind of wiring either.

 

[Lt.Dan]

When I installed my CT sensors, I opened up the panel below my meter, which you are typically not suppose to be able to see, and I found out my 200a Service at my house was installed with only 1/0 Aluminum cable, and it even looks like it was stripped with a steak knife, kicking several of the conductors.... smh...

 

[B-Mod]

When I installed my CT sensors, I opened up the panel below my meter, which you are typically not suppose to be able to see, and I found out my 200a Service at my house was installed with only 1/0 Aluminum cable, and it even looks like it was stripped with a steak knife, kicking several of the conductors.... smh...

View attachment 218822

Utilities use aluminum wire all the time, they must be peasants..........

 

[Zwy]

Was it in a vacuum oven

I've seen plenty of tarnished copper wiring. In fact I have this east german machine (from a country that no longer exists) made in 1964 that uses a sort of "mechanical computer" that has 18 large relays and a huge nest of copper wires. It can be "programmed" with use of plastic blocks. It is a sort of pre-CNC CNC if that makes any sense. Every few months when I try to use it I discover. Oh shit, it doesn't stop where it should... or it stops instead of reversing... etc All because of tarnished copper.

Those are connection issues, the copper wire itself is still functional. Clean the connections, add some Noalox or something similar to limit oxidation. Most likely if tinned copper had been used there would not be a connection problem. The connection problem is related to maintenance, it is not copper wiring failing.

2024 - 1964 = 60 years of service with most likely a very limited maintenance program. Amazing.

 

[Zwy]

Were the alloys so much worse? Or are these outlets and switches corroding aluminium wiring because of brass/copper being in contact with it? If the former I'm very interested what is it that makes today's aluminium better. Better purity? I always thought aluminium in the wires is as pure as possible (as opposed to alloys containing magnesium, silicone and copper found elsewhere).

Here, we use aluminium a lot (outside buildings, very heavy gauge wiring) and every electric supply store has special crimp things and even screw blocks one can use to safely connect aluminium and copper wiring. I don't think it is allowed for internal wiring.

You are agreeing with his post. Using aluminum wire for entrance cable does work but also requires proper rated terminals and use of an antioxidant. Not using antioxidant will result in failure down the road, many times under 10 years.

Back on the farm we ran aluminum triplex from building to building overhead. We also had problems in less than 20 years with oxidation and incompatible connections such as using a copper split bolt (wrapped tightly with electricians tape). The reason aluminum triplex was used was cost, large cable sizes for heavy loads over long distances. It is overhead which helps with heat dissipation. When repairing the connections, we started using antioxidant in the process as the industry realized there was a problem and introduced antioxidants. I have aluminum URD direct burial for my shop feed from the pole. The alloy is designed for this purpose. It requires antioxidant at any connection. I would not use aluminum for any feeders in a building or any aluminum wire past the breaker panel.

If the machine you mentioned in the previous post that is 60 years old used aluminum wire, it would have been junked 40 to 50 years ago. The connection oxidation would just destroy the aluminum and probably the connecter, it was built without an antioxidant.