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I recently bought a power strip with a surge protector and it came with this warning.

Do not install this product if there is not at least 10 meters (30 feet) or more of wire between the electrical outlet and the electrical service panel.

This question mentions that protection devices in series can interfere with each other, such as the breaker/fuse in the service panel and the surge protection (MOV or otherwise). How would a surge protector interact with the service panel protection? Does it change based on the types of protection in each? How would the length of wiring between the two affect it?

MackM
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  • [This Littlefuse writeup](https://www.littelfuse.com/~/media/electronics_technical/application_notes/varistors/littelfuse_transient_suppression_devices_and_principles_application_note.pdf) should clarify. – relayman357 Sep 11 '19 at 16:37
  • does the wiring inductance help here? at 1 uH per meter of wire (in freespace, the return wire being far away), thus 10uH. And at 1MHz transient frequency, you have 63 ohms of reactance. – analogsystemsrf Sep 12 '19 at 05:28

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Wires have resistance. The longer wires, the more resistance. The surge protector conducts during an overvoltage surge, and without external resistance too large currents can flow preveting the protector from clamping voltage. The resistance of wires will limit the current to the level the protector can operate.

Justme
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