30-amp service provides __________________________.

In recreational vehicles, 30-amp service is specifically designed to provide one 120-volt line at a maximum current of 30 amps. This type of service is typical for many RVs and supplies power for basic appliances and systems, such as lighting, refrigerators, and air conditioners.

The voltage and amperage combine to supply enough power for the essential electrical needs of most RVs, making it a common choice for smaller or mid-sized units. A 30-amp service is sufficient for running multiple devices simultaneously without overloading the system.

The other choices represent configurations that do not align with how a standard 30-amp service operates. For instance, a 240-volt line or multiple lines of 240 volts are characteristics seen in larger, more powerful electrical setups, typically found in residential or commercial applications, not RVs with 30-amp service. Thus, understanding the distinction in voltage and current capacity associated with 30-amp service is crucial for RV technicians to ensure safe and efficient electrical supply management within recreational vehicles.