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CharlieG
2011-07-15, 08:35
This week there was a ďlightening eventĒ at my house. I use that term because I donít want to give the impression my house was ďstruck by lightningĒ. My son (who is living with us between semesters) was in my garage at the time with the door open. He said the light and the thunder happened at the same time, the thunder so loud he wanted to cover hi ears, the light so bright he closed his eyes, and he could feel static electricity in the air. The hair on his arms laterally stood up.

This event took out the control panel of my alarm system, the Ethernet plug on my cable modem, the Ethernet plugs on my router, the Ethernet plug on my Squeezebox Touch, and the output side of my integrated amp. All of this I guess would be the low voltage side of things. All of these components were plugged into surge protectors, but it really doesnít look like there was a surge on the mains. All the devices would power up. My cable company was able to communicate with the modem but no data would pass through the Ethernet plug. I have replaced the modem. The router could not receive anything. It too has been replaced. The Ethernet cables have been replaced between all devices. The Touch canít detect a wired connection anymore (even with the new modem, router, and cables). It will however connect wirelessly to the new router. This morning after getting everything back on line, I realized I had no sound from my amp. I tried a switching to a different coax input, still no sound. I took the Touch from my den system (which still works) but no joy. I switched to the RCA output of the second Touch, still no music. I guess I need to move one of my speakers to the den and see if it will play there.

Is it even possible the wireless section of the router drew the static electricity into the low voltage side of these devices?

BigPotato
2011-07-15, 11:07
How was the Touch connected to the amp? Digital coax? If so, I'd suspect the path was:

lightning
ground
cable feed
cable modem
ethernet
touch
digital audio coax
amp

CharlieG
2011-07-16, 11:02
How was the Touch connected to the amp? Digital coax? If so, I'd suspect the path was:

lightning
ground
cable feed
cable modem
ethernet
touch
digital audio coax
amp

Yes that does make a lot of sense. Iíve done a little bit of research and found surges though coax cables can be just as damaging as through mains. I never gave coax cable must thought until your response.

Surges through coax may also explain why I havenít been able to get routers to live a very long life here. I keep buying more and more expensive routers and they donít last any longer than the previous ones. I also have a Squeezebox Receiver which will no longer connect via Ethernet (after almost 2 years of trouble free performance). I replaced it with a Touch and now the Receiver is in a closet ;-)

I now have the cable routed through a surge protector in an effort to prevent a repeat of this.

I have now discovered the Damaged Touch no longer responds to the I.R. remote. I havenít yet decided what to do about the Touch and amp. All this expense comes three weeks after I replaced my computer (which thankfully was not damaged).

aubuti
2011-07-16, 12:48
That's the route I was thinking. I admit I don't know anything about the guts of a cable modem, but I'm a little puzzled that the surge didn't completely wipe out the cable modem, but only its ethernet port.

jmschnur
2011-07-16, 13:12
Would you think a fiber optic based modem (fios) would have the same issues. ?

BigPotato
2011-07-16, 15:28
Yes that does make a lot of sense. Iíve done a little bit of research and found surges though coax cables can be just as damaging as through mains. I never gave coax cable must thought until your response.

Surges through coax may also explain why I havenít been able to get routers to live a very long life here. I keep buying more and more expensive routers and they donít last any longer than the previous ones. I also have a Squeezebox Receiver which will no longer connect via Ethernet (after almost 2 years of trouble free performance). I replaced it with a Touch and now the Receiver is in a closet ;-)

I now have the cable routed through a surge protector in an effort to prevent a repeat of this.

I have now discovered the Damaged Touch no longer responds to the I.R. remote. I havenít yet decided what to do about the Touch and amp. All this expense comes three weeks after I replaced my computer (which thankfully was not damaged).

I'd contact your cable company and get them to verify that your cable feed is properly grounded and protected. If you explain that you've had a few cases of damaged equipment they may be more willing to investigate and check the feed.

BigPotato
2011-07-16, 15:33
Would you think a fiber optic based modem (fios) would have the same issues. ?

I'd think FIOS would be pretty immune to this.

CharlieG
2011-07-16, 15:50
I'd contact your cable company and get them to verify that your cable feed is properly grounded and protected. If you explain that you've had a few cases of damaged equipment they may be more willing to investigate and check the feed.

I think that's good advice. I will call.

Update: My speakers seem to be O.K.

Mnyb
2011-07-16, 23:41
You can conect your squeezebox via spdif optical to amp and use wifi .

Does not stop things from being blown up via the mains, but reduces possible paths.

CharlieG
2011-07-22, 14:55
Well, a technician from the cable company came out today and checked to see if the system was properly grounded. It was. He did re-do the confections, I guess mainly because I was standing there watching him.

This tech said he really didnít think the surge came from the cable. He thought my DVR and TV would have been damaged had the cable been the conduit.

I told him I now have surge protectors for the cable and he was not impressed. His thought was a surge from lightening would happen so quickly it would overwhelm the surge protector.

Any thoughts?

I shipped off my integrated amp today. The manufacturer has a $120 flat rate for repairs.

toby10
2011-07-23, 03:38
With surge protectors you need a high rated clamping speed (time it takes to detect the surge and engage the protection).
Not being a physics expert I suppose some surges are just too quick/close for anything to stop it, I dunno.

Another thing to look into is a surge protector at your electric panel, usually referred to as "whole house" surge protection.
It's just a surge device that is installed in a breaker slot in your box. You need one for each circuit (around here all homes have at least two circuits).
BUT.... these are not meant to be used exclusively. You should still have local surge protection at your devices (computers, A/V rack, etc..).

Another thing to look into is how well your electric panel is grounded. This is an area where builders will cheat because few think to ask about it, and even if you ask how would you know the grounding spike is actually xx feet into the ground? Also grounding spikes can deteriorate over time (rust, corrosion, etc..).

I had my grounding spike replaced and had two of the breaker surge protectors installed by a licensed electrical contractor all for under $150.
The original ground spike was only 4 feet and it broke when they tried to remove it as it was so badly corroded. The new spike is like 6 feet (might be 8 feet).
That contractor told me he can often just pull such grounding spikes out of the ground by hand cuz they are often only two foot in length, which is just not sufficient grounding.

westom
2011-07-23, 17:58
This tech said he really didnít think the surge came from the cable. He thought my DVR and TV would have been damaged had the cable been the conduit.

I told him I now have surge protectors for the cable and he was not impressed.
Everything he said (and more he did not say) is correct. For example, show me spec numbers for your protectors that claimed any protection. Good luck. A majority recommend it only because salesmen, advertising, and hearsay told them how to think. Protectors on cable are wasted money. Most cable companies recommend they be removed since it subverts cable signal. And because that short connection to earth (without any protectors) is best protection.

In every case, a surge is seeking earth ground. If the cable is earthed, then why would that surge seek earth via your TV? Well again, many people forget about electricity as taught in elementary school science. Does a surge enter on a cable, destroy a TV, then stops? Of course not. First a current is outgoing from the TV at the exact same time a surge is also incoming on another wire. If cable is the incoming path, then where is the other outgoing path to earth?

If no path to earth exists, then the incoming path also did not exist.

The most common reason for damage is, for example, a lightning strike to AC electric wires down the street. Now that surge is connected directly to every appliance in your house. But again, from elementary school science. What is the other outgoing path that must also exist? Lightning striking wires down the street selects which appliance makes a best connection to earth. That is the damaged appliance. All appliances have in incoming path. Only some also have an outgoing path.

Meanwhile, a protector adjacent to an appliance can even give that surge even more paths to find earth - destructively.

You had damage because you all but invited that surge to go hunting inside. Every wire in every incoming cable must be earthed short (ie 'less than 10 feet') to single point earth ground. AC electric is three wires. Each wire must make that short earthing connection. Informed consumers earth a 'whole house' protector (ie less than $50 in Lowes) to connect two wires to earth. And - this is more important - upgrade the only item that does any protection: single point earth ground.

Protectors are more than fast enough IF the connection to earth is short. How fast are protectors? A number that increases significantly when wire is to earth is too long, has sharp bends, splices, is inside metallic conduit, or goes over the foundation to earth. Wire length to and quality of earth ground should have more than 50% of your attention. Because protection is always about the only item that must absorb hundreds of thousand of joules - with no damage even to a protector.

Why did facilities even 100 years ago suffer direct lightning strikes without damage? Because the science and experience has been understood and proven for that long. Too many people today want magic solutions (fiber optic, plug-in protectors) because advertising is their information source. Instead, learn why direct lightning strikes without damage were routine long before anyone here was even born. Learn well proven science. A protector is only as effective as its earth ground.

Fozzy
2011-07-25, 11:14
We had a lightning incident here recently and the damage was fortunately limited to a pair of DSL/Wireless routers connected to my DSL lines and the Ethernet port of an Xbox360.

In the case of the wireless routers in at least one case the telephone line interface was damaged as well as the power adaptor.

It seems the issue in this case was most likely not a high voltage between the live and neutral wires of the mains but between the mains wires as a pair and earth (ground). In that case the path to earth is through the DSL router to the phone line which has one leg grounded and the damaged parts reflect this.

In the case of a cable line the same route is possible particularly if the screen of the coax cable is grounded. In this case grounding at the customers premises probably acts more to protect the cable company's equipment and that of neighbouring customers that it does to protect your equipment.

westom
2011-07-25, 12:27
In this case grounding at the customers premises probably acts more to protect the cable company's equipment and that of neighbouring customers that it does to protect your equipment.
If any wire enter your house without being earthed, then all household appliances (even the furnace) are at risk. That cable company wire is earthed so that a surge does not enter via their cable. All telephone wires (not just one) are earthed by a 'whole house' protector installed for free by the telco. Earthed also to protect all appliances.

But wires that most often carry surge currents into the house are AC electric. If you have not earthed all (typ. three) incoming AC electric wires using a 'whole house' protector, then no effective surge protection exists.

Dr Standler discusses this in his book "Protection of Electronic Circuits from Overvoltage":
> This situation could be resolved by the use of mandatory standards ...
> At this time this book was written (1988), the author saw no hope of
> such standards being adopted in the United States for overvoltages on
> the mains.

Assume two buildings are interconnected by an Ethernet cable. And that cable is not earthed at the service entrance of both buildings. Then a lightning strike to one building acts like a lightning rod connected to all computers inside the second building. Damage because that cable was not properly earthed where it entered each building. Every wire (all eight inside an Ethernet cable) must connect to earth.