I still think you are insinuating a surge protector or ups unit is basically snake water as it won't protect better than the built in iMac protection.
Surgex is a series mode filter. It will somehow stop what three miles of sky could not? Of course not.
Numbers say how well it filters. And other numbers for how well it will survive transients that blow through it. But it is only a filter. Its numbers define extremely limited filtering during a typically destructive surge.
BTW, it forgets to mention that a surge on its safety ground wire bypasses the Surgex and therefore bypasses protection provided by a Mac's power supply. They forgot to mention that part.
Surge protect
ion means you know where hundreds of thousands of joules dissipate. Martzloff (and Nuke61) discuss some surge sources including switching transients and lightning. These occur during normal operation or belore power is lost (not during power restoration). The transient seeks earth ground.
If a path to earth is via an appliance, then the appliance is damaged. See Figure 8 in Martzloff's 1979 paper to understand why:
http://www.eeel.nist.gov/817/pubs/spd-anthology/files/Coordination 1980.pdf
What is a best protector on an incoming coax (cable TV) wire? Coax is hardwired low impedance (as short as possible) to earth BEFORE entering the building. A wire connects the coax to earth. What Nuke61 called, "protection at the service entrance." Then hundreds of thousands of joules dissipate harmlessly in earth. What does the protect
ion? A wire connection to earth ground. No protect
or exists.
Telephone and AC electric cannot connect directly to earth. You make that same earth connection via a protector. A protect
or is one part of effective protection system when a surge connects to what does protection. Where are hundreds of thousands of joules harmlessly absorbed? Earth. What is the protect
ion? Earth.
Yes, this typically is very hard to understand. Because one must first unlearn advertising myths and hearsay. Protect
or and protect
ion are different components of a 'protection system'.
A reliable facility can have no protectors. But it must always have earthing - the protection.
Either a protector connects low impedance (ie 'less than 10 feet') to what does protection - earth ground. Or it only claims to protect from other (often not destructive) anomalies. Don't ignore that number.
So back to a Surgex or a UPS. Where is the always required and short connection to earth? None exists. Surgex spec numbers define a filter that will somehow block or absorb what three miles of sky could not stop? UPS claims near zero surge protection that gets hyped by hearsay into 100% protection? In both cases, no low impedance connection to what does protection - earth ground.
BTW, other surges exist. A USB device consuming too much power creates a different surge. Again, the word 'surge' describes something completely unrelated. The word 'surge' is even used to define a computer's undersized power supply. So what is one surge protector that protects from all these?
Without specific numbers, we have little idea which 'surge' is being addressed. Above discusses the one surge that does damage because it hunts for earth ground destructively via appliances (ie a Mac).
And yes, some surge protectors earth even direct lightning strikes harmlessly. Even the protector is unharmed. But most of your attention should focus on what does protection - single point earth ground.