Patent ID: 7626796
Filing Date: 2009-12-01
Classification: H02H

Abstract:
1. A power distribution unit for electrically coupling with an electrical ground and an electrical power source having a first phase line carrying a first current having a first phase and a second phase line carrying a second current having a second phase, the second phase being offset from the first phase, the power distribution unit comprising: a chassis; a two pole circuit breaker mechanically coupled to the chassis, the two pole circuit breaker having a first input terminal, a second input terminal, a first output terminal, and a second output terminal, in a first condition the first input terminal being electrically coupled to the first output terminal, in the first condition the second input terminal being electrically coupled to the second output terminal, in a second condition the first input terminal being electrically uncoupled from the first output terminal, in the second condition the second input terminal being electrically uncoupled from the second output terminal, the two pole circuit breaker configured to monitor a first level of electrical current flowing between the first input terminal and the first output terminal and a second level of electrical current flowing between the second input terminal and the second output terminal, the two pole circuit breaker being further configured to change from the first condition to the second condition when at least one of the first level and second level of electrical current becomes greater than a predetermined threshold, the first input terminal configured for coupling with the first phase line of the electrical power source, the second input terminal configured for coupling with the second phase line of the electrical power source; a plurality of electrical receptacles mechanically coupled to the chassis and accessible from outside the chassis, each of the receptacles having a first connector, a second connector, and a third connector, the first connector electrically coupled to the first output terminal of the two pole circuit breaker, the second connector electrically coupled to the second output terminal of the two pole circuit breaker, and the third connector electrically coupled to the electrical ground; and a ground indicating circuit comprising an optoisolator coupled between the second output terminal of the two pole circuit breaker and the electrical ground and between the first output terminal and the second output terminal of the two pole circuit breaker, the ground indicating circuit being configured to indicate whether the third connectors of the plurality of electrical receptacles are electrically coupled to the electrical ground.