What is single-phase power?

Single-phase power refers to a type of electrical power distribution that uses a single alternating current (AC) waveform. This arrangement typically involves two wires: one is a live wire carrying the current, and the other is a neutral wire providing the return path for the current.

In residential and small commercial applications, single-phase power is the most common form of electrical supply, as it is sufficient to handle everyday energy needs such as lighting, heating, and small appliances. The simplicity of its structure makes it easier to manage and less costly to install compared to more complex systems.

The other options, while related to types of electrical systems, do not accurately describe single-phase power. For instance, direct current circuits involve a constant flow of electric charge in one direction and don't utilize alternating current, and three-phase systems consist of three separate alternating currents, providing higher efficiency and capacity for larger loads. Low-voltage lighting systems can be powered by single-phase or other systems but do not specifically define what constitutes single-phase power. Therefore, the two-wire alternating current circuit succinctly characterizes single-phase power.