Does Concrete Conduct Electricity?

-Updated 6/22/2021

Depending on who you ask, you might hear different answers to the question of whether concrete can conduct electricity. While concrete can conduct electricity, it isn’t an effective conductor. Concrete is a much better insulator, meaning it can significantly slow down electrical currents.

Electrical conduction and insulation are measures of how easily electrons can move through a material. Concrete is made up of several different materials — namely aggregates, cement and water. Using aggregates that are more conductive will lead to concrete that is more conductive. The wetness of the concrete will also play into its electrical resistance.

Factors like these can cause the electrical properties of each block of concrete to vary widely. In general, however, concrete functions better as an insulator than as a conductor. Read on to learn more about concrete conductivity.

Conductors vs. Insulators

Conductors and insulators differ in how they help or hinder the movement of electricity. Conductors have very little electrical resistance, while insulators have a lot and can block the flow of electricity. Both have their purposes and are necessary for different situations.

A cable, for example, might have a metal wire inside to transfer the electricity and an insulating jacket to keep the electricity from reaching other conductive objects. Electricians often use rubber protective equipment and construction workers use non-conductive ladders to stop themselves from becoming part of an electrical circuit and experiencing a nasty shock.

Whether a material is a conductor or an insulator can be determined by measuring its resistivity, measured in Ω⋅m, where a high number indicates poor conduction properties and a good insulator. Conductors typically have a resistivity of between 10^-2 and 10^-8 Ω⋅m, while insulators reach between 10¹¹ and 10¹⁹ Ω⋅m. The areas between constitute semiconductors, with moderate levels of conduction.

Here’s how some common building materials stack up.

• Copper: Copper is a very strong conductor, with a resistivity of 1.68×10^-8 Ω⋅m.
• Glass: Glass is an insulator and has a resistivity between 10×10¹⁰ and 10×10¹⁴ Ω⋅m.
• Silicon: Silicon sits in the middle at 6.40×10² Ω⋅m.

Every material has some level of conductivity, but where it sits relative to others determines its usefulness.

Is Concrete a Good Conductor?

So, is concrete conductive or insulative, and does electricity travel through concrete? Concrete’s resistivity is tough to measure due to its differences when wet and dry and the wide variety that exists in its makeup. Some aggregate behaves differently, and the pores in concrete can create variation as well.

One study found that oven-dried concrete has a resistivity of around 10¹² Ω⋅m, placing it solidly in the insulator category. Of course, this can vary. The study also found that moist concrete drops all the way down to the status of semiconductor, with a resistivity of 10⁵ Ω⋅m. In general, dry concrete with a typical composition will be an insulator and not a conductor.

Despite concrete’s low conductivity, current can pass through cement. It will still conduct some electricity and is actually a better conductor than some other nonmetal materials like glass. Still, you don’t want to depend on it to complete a circuit.