ATC UPA-130 30 mm Power Alert Voltage Detector. The ATC power alert is UL and CSA rated. The ATC UPA-130 Power Alert reduces the risk of electrical arc flash by pre-verifying the electrical isolation from outside of a control panel. Hard wired to the circuit breaker or main disconnect, the UPA flashes whenever voltage is present. Engineered with redundant circuitry, the Power Alert is powered by the same voltage that it indicates.