Thoughts on surge protection

[RichStevenson]

I recently experienced an indirect lightning strike and lost everything that was connected to the LAN in the family room. When the strike hit, it threw 3 breakers, and 1 GFI in the kitchen. Once I reset everything, I was at first puzzled as to why I lost the equipment that I did since everything was on surge protectors. Then I realized that two items in the room survived. The stereo and the Nintendo Wii. That's when it occurred to me what probably happened. I use Powerline Adapters to extend my network between the home and my office, which is a separate structure. You can't plug the powerline adapters into a surge supressor, because it will filter out the higher frequencies that it uses to communicate. That one powerline adapter was one of the items that died from the strike, and it was connected to a network switch. Everything connected to the switch took a hit as well, including the vip722k. The stereo and Wii were not connected to the switch. So I figured I had a good idea on where that transient voltage traveled from.

So I installed a whole house surge protector, as well as threw a network cable surge protector on the line coming form the powerline adapter as my first steps. I also insured proper grounding both inside and out of the Sat. system.

On the Sat. side of things, not only did I lose the 722, but one biplexer, and the TRIA <--? on the dish itself. So now I'm wondering if the excessive voltage didn't come in through the coax, through the receiver, out the ethernet port, through my switch, to the other A/V equipment.

Figuring I would never really know, I started looking for surge protection for the lines coming into the house. Did my research here, but am still a little confused. I see that it would probably degrade the picture and/or cause other issues.

Am I worrying too much about this? I would just really hate to have something travel down the coax and bypass everything I put in place for protection. I know nothing will save me from a direct strike, but I'm just trying to button things down as much as possible.

Thanks,
Rich

 

[raoul5788]

to Satelliteguys Rich!

I'm not an electrician, but it sounds like you have done about all you can. Like you said, nothing will help with a direct strike.

 

[Hall]

A "surge" protector, at least the typical ones, will by no means protect against a lightning strike or an indirect strike. They protect against overvoltage that may come from the power company, for example.

As noted, there's limits to what you can do. Lightning rods properly installed are an option ! Lightning can hit telephone lines, cable TV lines, satellite dish and it's lines, etc but those lightning rods won't help there (at least I don't believe they will and I'm not sure if you can tie these systems together).

 

[RichStevenson]

Thanks for the replies guys. I guess what I'm asking is should I worry about protecting the coax? Not against lightning, but against excessive current that may get onto the line and make it to the receiver. When the indirect strike I mentioned occurred, there were no melted wires, or scorched equipment. I actually opened the blu-ray player, and not even the caps were swollen. So I'm assuming the amount that came through was enough to cause damage, but not enough to leave any visual signs of it.
Again, first suspect was the powerline adapter. But i'm thinking the same the could, or did, happen through the coax, and just back fed through the LAN switch to the equipment connected.

 

[westom]

When the indirect strike I mentioned occurred, there were no melted wires, or scorched equipment.

First, damage occurs because a current found a path incoming and outgoing through electronics. Bot paths must exist to have damage. A lightning strike to AC wires far down the street is a direct incoming path to all appliances. Which are damaged? Which also made the best outgoing path to earth?

Second, and this is difficult for many. A surge is a currrent source. That means voltage will increase as necessary to blow through anything to earth. No protector (not one) will stop or absorb that surge current. Despite so many myths based in that concept, nothing adjacent to electronics even claims to protect from that current.

Third, protection is always about connecting that hundreds of thousands of joules to what does protection. Not just any ground. Single point earth ground.

For example, the dish is earthed. So a direct lightning strike goes directly to earth without passing through the LNB. Excellent protection. No LNB damage - if earthing is done properly - ie low impedance. Any sharp wire bends, splices, metallic conduit or even a longer ground wire means seriously compromised protection. Will increase impedance.

Treat the dish and house as if two separate structures. Each structure must have its own single point earth ground. That means AC electric, telephone and satellite dish wires all make a low impedance (ie 'less than 10 foot') connect to the same earthing electrodes. Not just some wires. Every wire. IOW a dish coax must enter at the same location as AC electric, etc. Otherwise protection is compromised.

A relevant example. Lightning strikes a tree to connect a cloud to earthborne charges maybe 3 miles distant. Some 20 feet from that tree is a cow. Killed by an indirect strike? Of course not. A direct lightning strike also killed the cow. Cow had four legs - four earth grounds. Therefore a shortest path from cloud to earthborne charges was up the cow's hind legs. And down its fore legs.

Same problem can explain why a satellite receiever is harmed. If AC electric, telephone, cable, and satellite dish do not have a common earth ground, then something inside may conduct a direct lighting strike - destructively. For the same reason that cow died. Protection always means that surge current never need enter the building. Then superior protection inside all appliances is not overwhelmed.

Fourth, no protector does protection. Either an incoming wire connects directly to the earth ground (ie satellite coax) - no protector required. Wires that cannot connect directly (ie telephone, AC electric) are connected via a protector. But in every case, protection is defined by what absorbs hundreds of thousands of joules. Single point earth ground. Protection means that current need not find earth destructively via appliances.

To say more would require further details. Remember, a picture for protection includes the entire house, a dish, a cloud, wires in every incoming cable, and geology beneath that house. Protection always means no surge current - even a direct lightning strike to AC wires far down the street - need find earth destructively inside via electronics.