In the traditional method of switch status detection, the switch is provided with metal contacts suitable for low voltages and currents. Unfortunately, the company says, a ground fault in any wire leaves the relay in a de-energized state, despite the switch being closed. This problem is solved in the Z789 zener diode through the use of unique quasi ground floating wiring.

The Z series barriers are available in one, two and three channel versions and more than 75 models for ac and dc applications. A replaceable fuse version facilitates circuit loop checks and reduces installation cost and space. Multi-level terminal blocks allow easy wiring.
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