To supply power from the primary distribution system to the 16 low-voltage outputs of the Secondary Distribution Center, what must occur first?

To supply power from the primary distribution system to the 16 low-voltage outputs of the Secondary Distribution Center, what must occur first?

• A. Direct connection to LV outputs
• B. Get stepped down by the 150 kVA transformer
• C. Increase voltage
• D. Switch to secondary bus

Answer: (B)

The key idea is matching voltage levels between stages. To feed the low-voltage outputs of the Secondary Distribution Center from the primary distribution system, you must reduce the high primary voltage to the low voltage required by those outputs. That voltage reduction is accomplished by the transformer, and in this setup the 150 kVA transformer provides the necessary stepped-down voltage and capacity to supply the 16 LV outputs. Directly connecting LV outputs to high-voltage primary would expose equipment to dangerous voltage and is not permitted. Increasing the voltage would move you further away from the required LV level. Switching to a secondary bus doesn’t change the voltage on its own—you still need the transformer to step the voltage down before feeding the LV outputs.

The key idea is matching voltage levels between stages. To feed the low-voltage outputs of the Secondary Distribution Center from the primary distribution system, you must reduce the high primary voltage to the low voltage required by those outputs. That voltage reduction is accomplished by the transformer, and in this setup the 150 kVA transformer provides the necessary stepped-down voltage and capacity to supply the 16 LV outputs. Directly connecting LV outputs to high-voltage primary would expose equipment to dangerous voltage and is not permitted. Increasing the voltage would move you further away from the required LV level. Switching to a secondary bus doesn’t change the voltage on its own—you still need the transformer to step the voltage down before feeding the LV outputs.