Proper procedure requires banks to always be energized from the __________ side.

Proper procedure requires banks to always be energized from the __________ side.

• A. Low side
• B. High side
• C. Mid side
• D. External side

Answer: (B)

Energizing a transformer bank from the high-voltage side means feeding it from the source side, not from the secondary. This keeps the unit connected to the upstream breakers and protective relays in the proper sequence, and prevents backfeeding into the source if something in the bank is energized or faulted. If you energize from the low-voltage side, the high-voltage side could be energized through the transformer in an unintended way, which can surprise personnel and complicate isolation and protection. By using the high side for energization, you maintain a controlled, predictable energization path and ensure the protection systems respond correctly.

Energizing a transformer bank from the high-voltage side means feeding it from the source side, not from the secondary. This keeps the unit connected to the upstream breakers and protective relays in the proper sequence, and prevents backfeeding into the source if something in the bank is energized or faulted. If you energize from the low-voltage side, the high-voltage side could be energized through the transformer in an unintended way, which can surprise personnel and complicate isolation and protection. By using the high side for energization, you maintain a controlled, predictable energization path and ensure the protection systems respond correctly.