Forget the Carrington Event, check out the New York Railroad Storm

Newer data has indicated the 1921 "New York Railroad Storm was greater in magnitude and effect than the 1859 Carrington Event . ...Data on the magnitude of the Carrington even is based on a single station record from India. Researchers went to multiple ground station in the US and EU looking for additional data. Correlated, it shows the 1921 solar storm to be stronger than the 1859 event.

Some areas reported telephone exchanges catching fire, which caught my attention owing to the robust lightening protection and grounding used in the PSTN equipment.

Aurora were visable in the Eastern United States, with additional reports from Pasadena California where the aurora reached zenith.

For your research and edification.
If we get hit with another large Flare/CME with the weakening magnetosphere, things will get ugly, fast..


Very detailed report
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Historical records of ground‐level geomagnetic disturbance are analyzed for the magnetic superstorm of May 1921. This storm was almost certainly driven by a series of interplanetary coronal mass ejections of plasma from an active region on the Sun. The May 1921 storm was one of the most intense ever recorded by ground‐level magnetometers. It exhibited violent levels of geomagnetic disturbance, caused widespread interference to telephone and telegraph systems in New York City and State, and brought spectacular aurorae to the nighttime sky. Results inform modern projects for assessing and mitigating the effects of magnetic storms that might occur in the future.


Locally, the grid is very well protected owing to prior events effects being noted and protection engineered into the grid system.
Lesser 48, not so much.
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Let's not forget the prepper mantra -
"If it has happened before, it will happen again"

 

Most of the old telephone systems used carbon blocks to bypass high voltage pulses to ground and were 2 closely spaced pieces of carbon, one on the line and one tied to ground. They required 600 or more volts to arc across, but once the arc was established, their resistance due to the arc dropped and they were able to handle large voltages and currents. In the 1960's I worked at the tail end of the copper age of phones. El Paso Tex had lines that ran to Denver, Sweetwater Tex, and San Bernardino Calif. The system used 165 gauge copper or roughly #6 wire and most had been in place for over 60 years. At certain times of the year there were many lightening strikes and the system handled them well, failed but easy to bring back up. Had to ground the lines when working on them as the difference in ground potential between one end and the other was often in the 100's of volts. All the switches, transformers, switchboard were on the protected side and it worked. I don't know if you would even know if an emp pulse hit as you were expecting and prepared for high voltage high current pulses and the system was designed to handle it. I would imagine that a wire designed to safely handle a 50 amp current would resist an emp a little better than a trace on a circuit board that may well be measured in the thousands of an inch or components with conductors in the millionth of an inch, YMMV

 

I worked as a Central office wire monkey right out of high school.

 

If it can take a lightning hit an EMP probably won't fry it.

 

These aren't a true EMP
These effects come from current/voltage induction into the wire by a 'vibrating' geomagnetic field. This has a much greater effect over time and may contain multiple 'spikes' of varying intensity. A single, ~100kM long, telegraph wire, parallel to the main field line direction in 1921 produced 1,900+ volts - leading to a fire in the telegraph control center..

Some years back, I was part of the team turning up the first Fiber optic system between Alaska and ORE.

The cable was constructed with an outer copper layer (sheathed, of course) that made the cable a single copper conductor between Ak and mid-coast OR. (Warrenton, OR to Seward is 1494 miles/2,404 kM.)

When the system was placed into operation, the second week saw significant voltage swings on the DC power system in Whittier, AK Senor management was freaking out. Fortunately the HAARP site was still operational.
I was able to show, on the HAARP magnetometer, that a minor solar storm was in progress, and thus the case of the power fluctuations. After that, the network operations center kept an eye on the spaceweather.com site for storm warnings.

.If a telegraph wire of 100kM can produce 1900+ volts at high current levels, you can imagine what a 2,400 kM long wire will produce....

Things could get real ugly....