BrickWall makes very effective series-mode surge suppressors (I use one at home).
Another company called SurgeX makes similar ones.
I'm pretty sure one or both of them make whole-house and commercial sized units.
One capable of protecting a 20 amp circuit goes for around $250-$300.
And, yes, they are entirely non-sacrificial, and can block surges up to "6000 volts and 3000 amps" (READ THE RATINGS).
(The joule and current ratings are irrelevant since the surge does NOT pass through the surge suppressor.)
In order to understand how they work, you have to look at the electric grid as a SYSTEM.
The way something like a lightning strike works is that an electric charge builds up between the clouds and the ground (at this point it's a voltage potential).
This potential eventually finds a path to ground, and the stored current drains to ground through this path... and we're talking about a huge amount of current (at that point it's a current spike to ground).
The power grid actually already has heavy duty circuitry designed to give the majority of the current contained in the strike a path to ground.... but a residual of several thousand volts typically remains.
(That residual is the voltage drop in the power grid itself caused by the current spike from the surge.)
However, even though this system is somewhat effective, the voltage on the 120 VAC line going to your house may jump to several thousand volts for a VERY brief period of time.
There are essentially two ways of dealing with this and protecting your equipment.....
You can shunt it to ground (provide it an alternate path to ground).
Or you can simply BLOCK it so it cannot get into your home or your equipment.
The premise that "the surge MUST find a path to ground", while true in general, is also an oversimplification in the context of protecting one home or one circuit.
There are in fact MANY paths to ground, including the surge protection on the power grid, and the circuitry in your neighbor's house.
One way to protect YOUR equipment from the surge is to shunt it to ground (offer it another path).
This is the way MOV-based systems work.
The main catch is that we're looking at a truly amazing amount of current.
The problem is that the components designed to do this essentially wear out over time (they suffer degradation each time they "fire").
Eventually they fail.
(Note that most better surge suppressors have an indicator LED that tells you when they need changing.)
The main benefit of MOV based systems is that they are quite effective and VERY cheap.
Another way to protect your equipment, which is what the BrickWall and SurgeX use, is to simply BLOCK the surge from entering.
Don't worry, it WILL find another path to ground, somewhere else.
Here are the pluses and minuses.....
- series mode surge suppressors tend to be bigger, heavier, and more expensive
- MOV-based suppressors tent to be small, light, and cheap
- series mode suppressors add a small amount of line resistance
(at rated load a BrickWall 20A unit will drop about 1V off your line voltage as seen by the load)
- MOV-based suppressors add NO extra line resistance, and do not cause any drop in line voltage at the load
- series mode suppressors are non-sacrificial (they do NOT wear out)
- MOV-based suppressors are sacrificial (they wear out over time - and, when they do, they may either burn out, sometimes violently, or they may simply stop working)
- series mode surge suppressors start taking effect just a few volts above normal voltage
- MOV-based suppressors generally start taking effect quite a bit above normal peak line voltage (so they don't protect equipment from small surges at all)
- series mode suppressors are inherently very good at suppressing all normal forms of line noise
- MOV-based suppressors inherently do nothing to filter out line noise (although many units include other low-cost line filtering)
- series mode suppressors work well on short sharp transients, which is the sort normally seen from lightning strikes, but do NOT work well on long-duration types of surges (like plain old poorly regulated line voltage)
- MOV-based suppressors work about equally regardless of the duration of the surge (but they don't do anything for minor fluctuations in line voltage either because they don't cut in at all unless the surge is pretty large)
- series mode suppressors, because they do NOT shunt current through themselves, can effectively handle a surge of infinite current (just as your $5 water faucet can hold back an entire reservoir)
- MOV-based suppressors, because they ARE required to shunt the entire surge through themselves, always have a capacity limit
(also, because they shunt that current to ground, they must dump that huge amount of current through your ground wiring, which may damage it, or cause a voltage surge ON YOUR GROUND LINE, which may damage equipment)
(in addition, because of this, a MOV-based suppressor RELIES on a good solid ground connection to protect you; a series mode suppressor can provide better protection with a weak or limited ground connection
As you can tell, I'm a bit of a fan.....
To me this seems like the sensible way to go about surge suppression.
I could offer a testimonial that "I've never lost a piece of audio or home theater gear that was plugged into one of these".
However, it wouldn't count for much, because I've always lived in areas where power surges were uncommon, and I don't recall ever losing a piece of unprotected equipment either.