Best electricity conductor: Is aluminum, gold, rubber, wood, copper, or brass conductive?

Wire Guts is committed to bringing information on some of the most interesting topics in the built world. Sometimes it has to do with building materials, and other times it may have to do with other topics that we get asked about a lot. 

Conductivity is one of those interesting topics we couldn’t help but sit down and write an article about. You guys, our readers, are curious about what causes a material to be conductive. You are also curious about which metals will conduct and which won’t. 

aluminum ruler

So, we sat down to determine which materials you were interested in. Various grades of carbon and aluminum are used in the built world. However, they’re not the only materials you guys are interested in. 

Thermal paste and silicon were simply some of the topics we found that this article would cover as well. We may even split it up into two articles when we get asked about more materials. 

Why do metals conduct electricity?

Let’s cover some bases before we proceed. All metals will conduct electricity to an extent. However, some are much better at it than others.

Some materials have other limitations, and they may not practically be used for the purpose in the industry. 

Copper and aluminum are the most common types of materials used in wire, so you may probably already know how they rank. 

Let’s explain what that means. 

wire

Material IACS (International Annealed Copper Standard)

The International Annealed Copper Standard is a benchmark that measures conductivity in various materials. For that reason, copper is benchmarked at 100%. Other materials are then a lower or higher number compared to it. 

It helps explain how various materials compare to copper, and thereby also to each other. 

Does aluminum conduct electricity?

aluminum ruler on a countertop

You’d probably be surprised to know that aluminum is not a naturally existing metal in nature. It’s a mixture of different materials, including bauxite ore. Bauxite ore consists of hydrated aluminum oxide. The material is then mixed with iron oxide and silica to give you alumina. 

Aluminum is a great conductor of electricity, but it’s not the best there is. On the IACS scale, aluminum has a rating of 61% compared to copper’s 100%. Copper is substantially better, but it’s also more expensive. 

Despite this, aluminum and copper are the two main materials used for wire. If you’re out looking to purchase wire, you must make sure to find out which gauge is right for you. When you’ve found the amp requirements, you can find the gauge that can support the necessary amperage. 

extension cord

With aluminum being a worse material than copper, you’ll need to figure out which material you’re getting. It’s often cheaper to buy the necessary aluminum cable than it is to go for copper. 

Copper is also significantly heavier than aluminum. Although copper is better at conducting electricity than aluminum, aluminum is better by weight. Aluminum has the current-carrying capacity of two pounds of copper.

Aluminum’s density is 2.7 g/cm³. Copper’s density is 8.96 g/cm³. Temperatures may slightly affect it, but those are generally the accepted values. It means that if you have 1 cm³ of copper, it’s 3.3 times as heavy as the comparable amount of aluminum. 

If you have one pound of aluminum, you will have 3.3 times the amount of material compared to if you had one pound of copper. 

For cost reasons, aluminum is very popular for electrical purposes. You’ll find it used inside RVs, ACs, and more. Whereas copper used to be more widely used, aluminum has proven to be the uprising material that is frequently replacing it. 

Construction is often about the associated cost as well, and aluminum exceeds the performance of copper on that front. Long-distance power lines and distribution on the utility grid all make use of this material.

By weight, copper is typically three times as expensive as aluminum is. Then you also have to remember how you get more volume of aluminum for the same amount of weight due to the differences in densities. 

Does water conduct electricity?

Water can be a very good conductor of electricity. However, it isn’t always the case. Read on to figure out when you shouldn’t be afraid that you could get electrocuted if there’s a power source in contact with the water you’re sitting in. 

There’s a reason why there’s this image of a hair dryer being dropped in a bathtub of water. It’s because water is typically conductive. Let’s repeat. You don’t want to be sitting in a bath full of water if there’s a hair dryer that may accidentally be dropped there. 

Typical water contains charged ions and impurities, which is what gives it its conductive properties. Without it, you could sit in a tub of water and have a hair dryer fall in. It wouldn’t be an issue. 

Water and electricity are such bad news because of the impurities. It creates a dangerous pair. Even if you were to put “purified water” in a bathtub, it’s not an experiment we’d be keen to explore. There’s a bit too much at stake!

Does pure water conduct electricity?

Pure water does not conduct electricity because it does not contain any of the materials through which the electricity can flow. It’s a better insulator than anything else, and electricity will not flow through it unless the necessary requirements are available. 

Does salt water conduct electricity?

On the other hand, salt water is a great conductor of electricity. You can get a light bulb to shine by using this substance. Building a saltwater circuit is a fun experiment that you can do in a classroom to illustrate the purpose, and Home Science Tools has a good guide on how to do it. 

For that reason, saltwater is great when it comes to being used for renewable energy. Salt that is added to purified water will change its chemical composition. The sodium and chlorine ions are pulled apart, which increases conductivity. They’re floating apart, and what used to be a good insulator has now become a good conductor instead. Science is fascinating!

If you’re a teacher, be sure to do this with your elementary or middle school children. They love seeing rather than just hearing about it. 

To get you started, you’ll need the following items:

  • Tongue depressors
  • A 3.7-volt light bulb in a socket
  • Aluminum foil
  • 9-volt battery
  • Salt
  • Copper wire
  • Tap water
  • Masking tape
  • Cup

Go to the website we linked to above to get the full instructions on creating a DIY saltwater circuit. 

Does gold conduct electricity?

Yes, gold is a great conductor of electricity. It’s even better than aluminum, although worse than copper. Gold’s IACS rating is 70%, with copper’s 100% showing that there’s a reason copper is being used for wire and gold isn’t.

Gold is a very expensive metal, and there would be no reason to put it in traditional wires if it was also worse at performing the job than copper is.

However, there are places where gold wires may serve a function. Microchips are one of those places as high resistance to oxidation and corrosion is required. At the same time, the microchips perform a very specific action. Electrical fluctuations could be detrimental to their performance. 

In those instances, a thin gold plating is commonly used. 

Does steel conduct electricity?

Did you know that steel is used in the underwire of bras? Yes, it’s true. While plastic is also used, it’s not nearly as common. 

Steel can conduct electricity, but it doesn’t do it very well. Steel’s IACS rating is 3 to 15%, indicating that copper is roughly 6 to 33 times better than steel is. However, it is used for short-range transmission lines requiring high-voltage capabilities. 

Is stainless steel conductive?

While all metals are somewhat electrically conductive, stainless steel doesn’t do a very good job. Despite being very bad at transporting electricity, there are applications where it is used. Type 316 and 304 are very resistant to corrosion which still gives them a practical application in the industry. 

Freestanding junction boxes and wall-mount enclosures are some examples that can be found despite its shortcomings compared to copper. 

Within an IACS rating of 2.5 for stainless steel type 304, copper performs 40 times as well as stainless steel for conducting electricity. Meanwhile, stainless steel type 316 has a rating of 2.3. It means that copper performs 43 better at the job.  

Is dielectric grease conductive?

Let’s start with a brief explanation regarding what Dielectric grease is so that we can get into the nitty-gritty. It’s obviously a material that contains the word “electric” as part of its name. However, what does that mean in terms of its chemical properties? 

Dielectric grease is popularly used in garages, although it isn’t required the same way oil or coolant. Dielectric grease acts as a protectant on car battery terminals and sparks plug boots the same way that car wax does. 

Despite its name, dielectric grease is not an electrical conductor. Rather, it acts as an insulator. The grease will act as a protector, and there are no downsides to using it as it helps prevent corrosion where it’s applied. 

Does rubber conduct electricity?

The rubber acts as an insulator and does not move electricity. If it did, it wouldn’t be possible to wrap it around wires safely. 

When the protective coating on wires gets damaged, it’s important to either fix it or change out the wire. You will otherwise have exposed live wire when you’re using it. It’s a major fire hazard and should not be taken lightly. 

Rubber is great at stopping electrons from being able to move freely. If conducting electrons are added to the rubber, the answer would change. 

Power lines and other high-voltage places may still be able to conduct electricity through the rubber. However, it is usually a great insulator and is used by electricians as gloves. There’s a reason why it’s a great idea to wear rubber-based shoes if there’s lightning outside. The current seeks the easiest way to get to the ground, and rubber shoes may keep you from being it. 

Is graphite conductive?

Graphite has free electrons that act as charge carriers the same way that other metals do. However, it does not mean it’s a good electrical conductor. Graphite’s IACS rating is just 0.22% compared to copper’s 100%. 

It means that if you want to be transporting electricity, copper does it 454 times as effective as graphite does. Despite this, it’s still used in electrochemical electrodes and brushes. 

Does wood conduct electricity?

Wood acts as a decent insulator and does not conduct electricity very well. It’s important to know that everything is relative. While it may not be as good as metals, it’s better than other materials like rubber and glass.

Besides its stiffness, the higher conductivity than rubber means it’s not used as a wire insulator. It’s important to know that high-voltage power does not have an issue going through a piece of wood for that purpose.

It’s also why you often see lightning strikes wood on a field. It’s a tall material that stands in the middle of an open field and provides the lightning easier access to the ground. 

Does copper conduct electricity?

Copper is a great conductor of electricity and is commonly used in all sorts of wires. However, it’s not the best at transferring electricity either. So, how come it’s so prevalent for electrical purposes? 

If you’ve been reading from the start of this article, you’ll know a thing or two about copper by now. It’s such a good conductor that there’s a standard that is benchmarked against it. With an IACS rating of 100, it beats many alternatives. However, silver still has a higher IACS rating than copper does. 

For other reasons, it is not what you will find inside a cable. 

Is brass conductive?

Brass is a material that contains copper. However, brass is significantly less conductive than copper is. It has a bunch of additional materials added to it that make it unsuitable for electrical purposes. 

Being an alloy of copper and zinc, brass has the ability to transport electricity. With an IACS rating ranging from 12% to 37%, it does not compare to a material like copper.

The various types of material mean that it is used in electrical applications despite its IACS rating. It’s still a high-strength that is able to transfer electricity where copper’s features aren’t needed. 

CuZn15 and Cuzn30 are the most commonly used variants in the industry. 

FAQ

Does aluminum conduct electricity better than steel?

Yes, it does. Aluminum has an IACS rating of 61%, whereas cast steel has an IACS rating of 10.70%. For that reason, aluminum is 5.7 better at conducting electricity than cast steel is. 

When you look at high alloy steel, its IACS  rating is 2.90%. In comparison, that means aluminum is 21 better at the purpose.

What type of metal does not conduct electricity?

All metals conduct electricity, but stainless steel is the worst at it, with an IACS rating of 2.5%. In comparison, it’s only 1/40 as effective as copper is. 

Why is gold not used in electricity?

Gold is used for some electrical purposes, but in a limited way. There isn’t enough of it to go around. Gold also only has an IACS rating of 70% compared to copper’s 100%.