Which voltage level is referred to as the voltage delivered to customers in distribution?

• A. Transmission voltage
• B. Primary voltage
• C. Secondary voltage
• D. Tertiary voltage

Answer: (C)

In a distribution system, the voltage that actually goes to customers is the secondary voltage. Power is transmitted at very high voltages to minimize losses, then stepped down to a primary distribution level and finally down again by distribution transformers to a low voltage that houses and businesses connect to. That final low voltage, typically around 120/240 V for residential service in the U.S. (with variations like 277/480 V in some commercial setups), is what customers receive. The higher levels—transmission voltage and primary distribution voltage—are used along the way but are not what ends up at customer meters. Tertiary voltage is an even lower level used for specific equipment, not the standard customer service supply.