Test device and alternating current power detection method of the same

A test device comprising:

• a plurality of test components;
• a plurality of power supplies electrically coupled in parallel each to receive an alternating current (AC) power through a first wire, a second wire and an earth wire to convert the AC power to a direct current (DC) power and supply the DC power to the test components;
• an AC power detection circuit electrically coupled to the power supplies in parallel to receive the AC power through the first wire, the second wire and the earth wire, wherein the AC power detection circuit determines whether a first voltage difference between the first wire and the earth wire is outside of a first predetermined range and determines whether a second voltage difference between the second wire and the earth wire is outside of a second predetermined range;
• and
• an alert module;
• wherein when the first voltage difference is outside of the first predetermined range and the second voltage difference is outside of the second predetermined range, the AC power detection circuit controls the alert module to generate an alerting signal.