In distribution stations, load transfer to a paralleled bank is achieved by opening the bank __________ side CB.

• A. Low
• B. High
• C. Mid
• D. Back

Answer: (A)

When two transformer banks are connected in parallel to feed a common low-voltage bus, transferring load from one bank to the other is done by isolating the bank on the low-voltage side. Opening the bank’s low-side circuit breaker removes that bank from the LV bus, so the entire load is carried by the remaining bank. The high-side remains connected to the source, keeping the bank energized on the HV side but out of the LV circuit, which is the safe and reliable way to shift load.

Opening any other side wouldn’t remove the bank from the load path; for example, keeping the LV connection would still let that bank contribute to the load or create undesirable conditions during the transfer. That’s why the low-side breaker is the correct choice.