What are GICs? Freshman physics 101: When a magnetic field swings back and forth, electricity flows through conductors in the area. It’s called “magnetic induction.” Geomagnetic storms do this to Earth itself. The rock and soil of our planet can conduct electricity. So when a CME rattles Earth’s magnetic field, currents flow through the soil beneath our feet.Québec is especially vulnerable. The province sits on an expanse of Precambrian igneous rock that does a poor job conducting electricity. When the March 13th CME arrived, storm currents found a more attractive path in the high-voltage transmission lines of Hydro-Québec. Unusual frequencies (harmonics) began to flow through the lines, transformers overheated and circuit breakers tripped.
A few years ago my cold water pipe from the street failed and I had to have it replaced with PEX. I immediately called an electrician to sink some grounding rods to meet code and an arrestor on the power feed into the house. I feel sorry for people that have only a cold water pipe ground and replace that with plastic that leaves grounding to chance. The electrician even thought to put a jumper at the water heater between the cold and hot copper pipes before I could ask him to do it.
I even put grounding rods in when I run a power line to a hot tub junction box, garage, shed or barn. They are a pain to drive into the ground, but worth it.