Step 1:
The main service entrance should be protected against high energy impulses that you will experience from lightning and utility switching activity.
Step 2:
The individual power distribution circuits as well as sensitive three-phase loads need additional protection against internally generated transients. This second step is characterized by protection level closer to the nominal voltage of the power supply.
Step 3:
Finally, there should always be surge protection installation directly at the sensitive single phase loads. This protection device will provide tight voltage clamping relative to the nominal voltage for effective protection from all internally generated transients, as well as protection from residual effects from up-stream protection devices. For additional protection against EMI/RFI, the load can also be protected with a combination surge and filter device (Surge Filter).
A conventional three-stage concept would include the following: |
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