In a CSP transformer, what happens when there is an overload on the secondary side?

• A. The primary winding disconnects
• B. The internal secondary breaker disconnects the hot legs
• C. The fuse in the primary opens
• D. The transformer shuts down automatically with a siren

Answer: (B)

When the secondary side is overloaded, protection on that side acts to isolate the fault. An internal secondary breaker trips and disconnects the hot legs on the secondary, quickly stopping current flow there. This local disconnection protects the transformer windings and connected equipment from overheating without forcing a full shutdown of the primary circuit. The other options describe actions that either cut power upstream or rely on an alarm, rather than the immediate, localized protection the secondary breaker provides.