Instead of connecting every chassis directly to ground through a grounding strap, one or more of the connections could be via a low-impedance inductor. For example, if a 1 mH inductor is used, the magnitude of its impedance at 60 Hz (ignoring its ac resistance) is 0.4 ohms while at 1 MHz its impedance magnitude is about 6 kohms. This ground connection through an inductor is a type of hybrid ground. If the noise or fault source on the shield is best modeled as a current source, then this inductor could raise the potential of the shield, which is probably undesirable. If the noise or fault source is best modeled as a voltage source, then the inductor could reduce the strength of higher-frequency noise and fault currents along the shield. In some safety applications, a maximum impedance to ground is specified at a specified frequency, which would place an upper bound on the value of the inductance. However, in other applications, so as to limit the maximum fault current, the minimum impedance to ground is specified, which would place a lower bound on the value of the inductance.

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