This. Keep in mind the Carrington event happened at a time in history when electricity wasn't even fully understood. The little electrical infrastructure that existed at the time was primarily telegraph lines. All of these lines were bare copper wire and the system was powered by battery (generators didn't exist yet) so you'd have a battery room/shack, a telegraph key and register and then miles of exposed copper wiring.
The most protection these systems had were very crude lightning arrestors going into the telegraph building to prevent a lightning strike from killing the operator. But its no wonder the exposed wires were sparking when the Carrington event hit. It wasn't uncommon to run these wires pretty close to one another (for alarm/fire telegraph systems) because under normal conditions a 1" air gap was more than enough protection for these low voltage systems.
Modern electrical infrastructure is significantly more robust, not to mention we understand solar flares and EMP fields much better than we did back in 1859. Even a flare more powerful than Carrington, or even an EMP from a nuclear blast, wouldn't be as bad as the doomers claim.