Chassis Ground

This terminal is often denoted using the chassis ground symbol of Fig(a). The electrical connection to earth, however, has been made (inadvertently) a nonzero resistance; it may be the table for all we know. In any event, there is no reason to except this chassis ground to be the earth ground.

A pseudo-schematic (some liberty was taken with the person's equivalent resistance symbol) of the situation is shown in Fig. If the equivalent resistance of the person is significantly less than the resistance of all other possible paths to ground… well, let's just say not all stories have happy endings.

The fact that "ground" is not always "earth ground" can cause a wide range of safety and electrical noise problems.

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