Customer calls and says no signal on all TV's.
I go out there and sure enough Xantech HD88cc5 component matrix switcher is fried. Lightning reported in the area but no other damage. Everything is protected as well as I know how. I get a new unit today and swap it out. Everything works except for outside cabana tv. I am powering the Xantech baluns back at the rack with protection but the outdoor Balun is also fried.
All power supplies tested good. I am assuming a surge came to the outdoor tv and passed through the component or digital audio cable through the cat5 back to to switcher and fried it? How do we protect against that?

Although, this is the 5th unit that we have had problems with, zones not working, baluns going bad, and so forth. I will never bid a job using this unit again but what happened? I did a job a long time ago where the cable box line was not running through a surge protection and fried an onkyo receiver through the hdmi. How can this be avoided?

 I'm not sure if you can ever be fully protected.  You can only do what you know is best.  

We're currently working on a system that had surge protectors everywhere.  Behind TV's, in the rack, etc.   The customer had a direct lightning strike in their yard.  It hit the cable line coming into the house and fried every piece of equipment in the house, and also fried numerous outlets.

Ouch!

The smartass answer is to move to Southern California. But really, every time I read about lightning strikes I cringe. It's impossible to eliminate this, and it looks like you're doing what you can to avoid it.

Hey, a sudden thought occurred to me -- at the risk of unleashing a whole new breed of tweaks on you, try contacting the local ham radio club. Those guys put up high towers and have more of a lightning problem than any residence!

As for California, okay, we've got earthquakes, but not tornadoes, hurricanes, salt eating through the car body in the winter, black ice making cars slide into one another. Not to mention that even when all is well in many places it's friggin' freezing. And/or "feels like" 180% relative humidity.

First, you must remember a concept taught in elementary school science. To have an electric current, both an incoming and an outgoing path must exist.

Second, I assume no 'whole house' protector was earthed at the AC breaker box. So lightning striking far down the street was also connected directly to every appliance. Every appliance had an incoming path. Only appliances with an outgoing path to earth would be damaged. Lightning is inside the building hunting for earth destructively.

Typically a best path to earth is via signal cables. Telephone, cable TV, and satellite dish are required (by code and Federal regulations) to be earthed. So that is a perfect outgoing path. Often damage occurs on electronics connected t the outgoing path.

Protection for over 100 years was always this. No surge energy is permitted anywhere inside the building. For example, three AC wires enter. Only one (neutral wire) connects directly to earth. Protection means every single wire - no exception - must be earthed before entering the building. We cannot connect other AC wires directly. So a 'whole house' protector must make that short (ie 'less than 10 foot') connection to single point earth ground.

Notice the so many requirements. No protector does protection. Either a protector connects low impedance (ie' less than 10 foot') to the protection. Or the protector can even make surge damage easier.

Every wire must be earthed to the same electrode. Cable TV needs no protector. A wire makes that connection better. All phone lines have long had a 'whole house' protect where telco wires connect to yours (the subscriber interface). Those educated by advertising would not know of anything in this paragraph. That solution has been well proven for over 100 years.

Protection is always done by earthing. Even lightning rods are only as effective as their earth ground. Protection is often forgotten because so many do not see it. Because so many only see a magic box. Protection is made even better by upgrading earth to both meet and exceed post 1990 National Electrical Code requirements. An earth connection must have no sharp bends. Sharp bends, splices, metallic conduit, and longer wires only increase impedance.

This is only an introductory summary of protection. You should have plenty of questions. Start by reading manufacturer specs on plug-in protectors. If it does protection, then you can post numbers for each type of surge. Those are profit centers; not protection.

Protection is always about where hundreds of thousands of joules are harmlessly absorbed. A protector is only as effective as its earth ground. Telcos all over the world operate computers and operators without damage or death during every thunderstorm. Over 100 years of well proven science.

Weston (also know as good elementary teacher)

Not a singe breaker in home was tripped. Not a single other piece of equipment was damaged. No power ever went off at home. The GFI on The TV was not even phased. We live in the South where we see Thunderstorms and lightning weekly.

In My experience, I have only had a handful of equipment fail. All of which seems to be the outgoing path you speak of. The most interesting fact of all, is I have had one Onkyo receiver fry. Everything else that has fried has been a Xantech product. Specifically the Baluns, and matrix switchers.

There isn't a simple explanation for this, but there is a complex one...

I can't speak for Xantech, but I can speak for our products. We too get calls from integrators that had field failures due to lightning and surges, and in many cases it's the only item in the house that had failed. On all our product returns we do a failure analysis to determine the mode of the failure, and what the likely cause was, as well as use this information to improve future revisions of our product. So what have we learned? It's all about ground.

Most of the surge protectors you are aware of attempt to protect the AC power lines. This is all fine and good, but they do not protect the other signal inputs and outputs of the unit. What is unique about video is that in order to get top performance, the signal MUST be DC coupled. That means there is an direct electrical path from all of the zones back to the rack. Not many other pieces of equipment require this.

Now back to grounds - when you have a surge event, there will be differences in ground voltage potential at different points in the structure. Some structures make that worse by having screwed up grounds, or old and faulty grounds, making the voltage potential worse. So for some moment in time, you can have one ground at 0V, and another at 30V, and the path of least resistance to equalize the two is your video cables. Even with surge supressors everywhere, equipment can't handle this. Only way prevent this is to fix the grounds. By the way, if you have more than one ground point, this gets worse.

"Ah, what about my network gear? It's never been a problem!", I bet you were about to ask. Well 10/100/1000baseT Ethernet is all transformer coupled and fully isolated, even with POE. This is possible because Ethernet waveforms are narrow band and optimized for going through a transformer, so they don't need the DC coupling as required for making stable video.

So what's a integrator to do? If cost is not a limiting factor, then fiber optics is your answer. With fiber, the medium itself is non conductive and gives complete electrical isolation, and no path for surges to travel through. However for cost sensitive projects, Cat5 will likely be used, and create a greater risk for video. There are Cat5 surge protectors, but as Westom had pointed out, they are only as good as the ground. Intrestingly, Coax cables for video offer some level of protection, since the shield has a large amount of copper wire and generally connects directly to the equipment chassis at both ends. This gives surge energy a low impedance path to ground without having to blast its way through IC chips (not that you should count on your coax shield as your protection, but that's what ends up happening).

So in summary:
1) Fix your grounds, check code compliance, single point grounds, etc.
2) Use surge suppression on your Cat5 A/V lines
3) Optically isolate with fiber where possible

And most importantly, set the expectations with your client that these are not cure-alls. Damage to electronics is a fact of life and that is what homeowners insurance is for. It's not practical to make their home into a totally protected 911 call center. You can do your best to prevent it, but you shouldn't be expected to fix this stuff forever for free.

It's like a worm that you cut in two
You think it died
And that you'd never have to see it again
But then it comes back
Twice as strong
ie less than 10'

All completely consistent with what was posted. For example, surges are microsecond events. Circuit breakers require tens of milliseconds before it even begins to trip. 300 consecutive surges could pass through a circuit breaker before it even thinks about tripping.

GFCI would not be tripped by a surge for the same reason.

Normal is for a surge to confront many appliances. But only one is damaged. For example, an AC mains surge was incoming to adjacent TV and VCR. Both have an outgoing path via the TV cable. But only the VCR is damaged. VCR acted like a surge protector. Since the surge found a better path to earth via the VCR, then protection inside the TV was not overwhelmed.

Your every observation is completely consistent with what was posted. Observations are often deceptive when those basic concepts are not first learned. That also was taught in elementary school science. "Spontaneous reproduction" was proven by those who knew by only using observation.

Protection means every incoming wire must be at the same potential where it enters a building. Earth ground (not safety ground) is the only ground that matters. If any incoming cable is connected to earth by a wire too long (ie not 'less than 10 feet'), then it is not grounded - not protected. Then potential differences exist. Then the surge is inside hunting for earth destructively via appliances.

Either that surge energy connects harmlessly to earth outside a building. Or that surge goes hunting for earth destructively via appliances. You probably did not know of that damaged VCR and undamaged TV example. It becomes ridiculously obvious when one first learns concepts understood even 100 years ago.

Protection is always - as in no exceptions - always about where energy dissipates. Either energy is harmlessly absorbed outside the building. Or that energy goes hunting destructively inside. A protector is only as effective as its earth ground.

BTW, Ben Franklin demonstrated the same concepts (as taught in elementary school science) in 1752. Lightning rods are about no current conducted to earth by a wooden building. 'Whole house' protector is about no current conducted to earth by appliances. Protection is always about the path used by current to connect to earth.