According to one aspect, an uninterruptible power supply system is provided including an input configured to receive input power, an interface configured to be coupled to a backup power supply and to receive backup power from the backup power supply, an output configured to provide output power derived from at least one of the input power and the backup power to a load, a power converter coupled to the input, a capacitor, and a shoot-through detector coupled to the capacitor. The shoot-through detector is configured to obtain a first voltage value indicative of a first voltage across the capacitor, obtain a second voltage value indicative of a second voltage across the capacitor, compare the first voltage value to the second voltage value, determine, based on the comparison, that the capacitor is experiencing a shoot-through condition, and provide an output signal indicative of the shoot-through condition.