What is the voltage of insulated conductors in a standard single phase service?

In a standard single-phase service, insulated conductors can operate at various voltage levels depending on the application and design of the electrical system. Typically, in residential settings, the most common voltage for single-phase service is 120 volts, which is often used for standard household circuits. However, single-phase systems can also function at 240 volts, especially for larger appliances such as dryers or kitchen ranges, which require higher voltage for more efficient operation.

The inclusion of 480 volts is also valid under certain industrial or commercial situations where single-phase services might be derived from a three-phase system that provides a phase-to-phase voltage of 480 volts. While it is less common, there are instances where you may encounter single-phase circuits utilizing this voltage level.

Therefore, since insulated conductors can indeed be found in applications operating at 120 volts, 240 volts, and even 480 volts, the correct understanding incorporates the variety of voltage levels present within standard single-phase services, confirming that all mentioned voltages are legitimate in different contexts.