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Undervoltage Release (UVR)

The undervoltage release (UVR) is an optional device on both manually and electrically operated Magnum and NRX/Power Defense circuit breakers. It opens the circuit breaker when its supply voltage falls to between 35–60% of rated voltage. If the release is not energized to 85% of its supply voltage, the circuit breaker cannot be closed electrically or manually. The opening time is 70ms.

The UVR operates instantaneously and will not ride through power blips. There is a time delay UVR that mounts externally to the breaker.

If installed, this accessory MUST be wired. If left un-wired, the breaker will not be able to close, as the UVR will never see the required voltage to energize.

Magnum UVR:


Magnum renewal parts

NRX renewal parts