Best protection works on all electric systems from 1920 knob and tube to 2018 wiring. On all two and three wire electric. Using fuses or circuit breakers. If that was not obvious, well, most here want to argue and post cheapshots rather than learn what was routinely installed in facilities that cannot have damage - even over 100 years aso.
Your telco CO suffer about 100 surges with each storm. How often after every storm is your town without phone service for four days while they replace that $multi-million computer? Never? Exactly. Because they also do not use that pathetic and ineffective protectors. Only used is what any homeowner can installed for only $1 per appliance.
Rather than admit to being scammed by advertising, propaganda, wild speculation, hearsay, and lies from peers, the naive instead have resorted to cheapshots.
Did brainwashed consumers fail to learn about best protection is installed for free and required by code on cable TV, telephone, satellite dish, OTA antenna, and other incoming wires? Unfortunately most here want to argue rather than learn what was well understood and implemented over 100 years ago. What can easily be installed in any hone ... if only a homeowner concedes how easily scams manipulate.
900 joules means is only absorbs 300 joules and never more that 600. A scam recommendation could not be more obvious.