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What is the latch check switch on Magnum and NRX breakers?

The Latch Check Switch (LCS) is an option for Magnum and NRX breakers that indicates when the breaker is "ready to close." There are two options: wired into the spring release, and remote indication.

The LCS wired into the spring release will not permit activation of the spring release until the circuit breaker is fully charged and the trip latch is reset. If power is applied and maintained to the spring release, an activation will occur when the circuit breaker is "ready to close."

The LCS for remote indication consists of one Form C contact wired to the circuit breaker secondary contacts for integration into external control schemes. This contact should NOT be wired in series with the spring release, as it will override the anti-pump feature of the electrical charging/closing system.

Magnum renewal parts

NRX renewal parts