Abstract: An information transmission system comprising a conductor operable to carry a desired information signal. A first tube substantially surrounds the conductor and a second tube substantially surrounds the first tube to define a substantially fluid-tight chamber therebetween. In another aspect, the invention provides an information transmission system suited to transmit information between a first electronic device and a second electronic device located a distance from the first electronic device. The system includes an information transmission line that connects to the first electronic device and the second electronic device. A conduit surrounds at least a portion of the information transmission line. The conduit defines a substantially fluid-tight chamber. A quantity of fluid is disposed within the chamber and a sensor is positioned to measure a parameter of the quantity of fluid. An indicator is operable to signal a breach condition in response to the measured parameter.

Abstract: Apparatus to monitor the continuity of grounding circuits of an electrical machine. The apparatus measures the resistance in the grounding and pilot circuits and deenergizes the electrical machine if the resistance in said circuits exceeds a predetermined value.