On a Sun Server X4-4 with four processors, the default Oracle ILOM configuration is to prevent the system from powering on if the power supplies are not connected to high-line (220-240VAC) power. However, for special test purposes with systems that include few options (and therefore have lower power demands), you can choose to override the default power policy and use low-line AC power (100-127VAC) to power-on the system.
Overriding the power policy disables power supply redundancy. When connected to low-line power, a minimally configured four-processor system still consumes more power than a single power supply can provide.
Powering on a four-processor system with low-line power and with low-line mode enabled causes a fault to be generated, and causes the fault indicator on the system to light. This fault is to be expected; it clears automatically once you go back to high-line power.
For more information refer to the Sun Server X4-4 documentation library at: http://www.oracle.com/goto/x4-4/docs