lightning storm

You should have immediately unplugged your audio system from the wall outlet.

It's possible slight damage may have occurred to some circuit board traces. It's called electronic rust. 

I would suggest you unplugged your audio system from the wall outlet during lightning storms. 

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Yes, it is probably EMI either entering directly into your system or EMI affecting your power lines.  In any even, it is better to turn everything off during a storm.  Even better is to unplug the gear because a direct hit of lightning could be powerful enough to jump the switch in your gear.

Even when lightning does not directly strike a power line the magnetic pulse is picked up by every cable nearby, from high tension lines to your house wiring, antenna cables and Internet provider's wiring.  

We don’t always know when a surge will come down the line so having a good surge protector is essential IMHO, but even then I would absolutely recommend unplugging when you know a big storm is coming through.  Sometimes I even turn off my HVAC and range as well, despite having a whole house surge protector.  

Thank you for your responses. Much appreciated and I will be turning everything off and disconnecting in the future.

How is "electronic rust" detected and repaired?

Storms can cause slight shifts in ground potential, which may temporarily aggravate grounding issues, causing hum or static. If you only heard static during a storm but it went away afterward, it was likely due to temporary EMI or line noise.

BTW, Electronic Rust has nothing to do with lighting or thunderstorms. It is an informal term often used to describe corrosion or degradation of electronic components or circuit board traces, typically caused by moisture, oxidation, or chemical contaminants. It’s not actual rust (iron oxide), but it behaves similarly by slowly damaging the delicate metal pathways that allow electricity to flow.

First question  unplugging it is a good idea ,but 2 nd what are you using 

for a line conditioner, Surge protector ? You Donot want anything that uses MOVs

they totally destroy your current capabilities  and should be avoided ,

and you should have Copper - plated recepticle ,for cheap brass oxydizes

try cleaning out a recepticle. 

Once again, I urge all Agoner's to invest in a whole house surge protector, when possible.

@jea48 , nice to see you here. I have always appreciated your knowledge of all things electrical.

bob

As a retire audio tech, I saw my share of lighting damage over the years. Unplugging is the ONLY way to totally protect your equipment, and that includes internet cable and any type antenna cables. Those also create a path to ground, and if connected, can be a source for damage. 

HAHA 😆 😅. Be careful with that back around 1998 when the strip protectors weren't so good a lightening storm fryed the transformer in my Kenwood receiver and no parts available so it was done. I did find a replacement on eBay for $475 I think it was. Get one of those big ones that the whole thing plugs into the wall , no cord at home Depot they have a $10,000 protection guarantee.

EMI damage? Recently my F150 sat next to a pine tree that took a hit. $5k damages to the electrical. Luckily no damage to my HT/music system however my modem & charger to my laptop did not fare so well. $1k deductible on the Ford so not as bad as it could have been. 

EMI damage? Recently my F150 sat next to a pine tree that took a hit. $5k damages to the electrical. Luckily no damage to my HT/music system however my modem & charger to my laptop did not fare so well.

I don’t think the damage was caused by EMI. More likely from an electromagnetic pulse (EMP).

 

Edit:

I ran across this device on the Net. Does it really work?

EMP & Lightning Protection for Vehicles (DC-12V-W)

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The Internet is filled with stories about lightning coming in via the cable modem and taking out entire HT systems via burned out Ethernet ports. 

Most Internet users rely 100% on Wifi, but for those of us who use it professionally or just don’t like to have Wifi problems we wire all our big gear up.  Our work computer, TV, music streamer, etc. and so I take a paranoid approach.   Using Ethernet is great for reliability but also leaves us more exposed to incoming surges.  

I use an external coaxial surge protector with gas discharge tube.   Internally I air gap the modem and router with fiber/Ethernet converters and at the end of long runs I use Ethernet isolators (not surge protectors) which are tested to UL 60-601

The lightening is 2.3km away from you. 

At the first sign of a storm simply go outside and hold up a tall metal pole to attract the lightening and hopefully divert it from your house. Works every time.

@Wolf_garcia

Perhaps flying an aluminum foil kite with thing copper "string". 

try taking the penny out of the electrical socket

 

Not just switch off, completely unplug. I lost my Luxman amp, Bryston CD player, and Martin Logan speakers in a lightning incident. Fortunately homeowner's insurance covered most of it, and Bryston stood by their astonishing warranty, otherwise I would have been out a very significant amount of money

Had a lightening strike that came in thru my dog's "invisible fence". Took out my computer and Bryston amp. Bryston service said it wasn't covered in their warranty BUT "this time" we'll fix it.  I'm a Bryston fanboy for life . . . but I do have a whole house and a protected separate circuit for my toys now. 

Good idea to avoid showers / baths as well.

My system was hit by lightening, it traveled through the coax cable line into my video processor via HDMI and then hit my projector. I had everything on quality surge protectors but it didn't matter. The electrician I took the equipment to for insurance purposes said that lightening likes to have a path in and out so having things plugged into different wall outlets is an issue. I have since purchased a PS Audio P15 Powerplant power regenerator. Not only do I have zero static on my line I power everything from one outlet (yes it is a pain to have a 50ft cord going to the projector along the ceiling in a wrap with the HDMI cord). The pool of capacitance it has is fantastic and it lowered the noise floor, the base is much more effortless, and the colors pop on the projector believe it or not. Plus there is a huge quality of life bonus, I've programmed everything to turn on and off in the correct order, what a luxury. Now the system is unplugged all the time, I check for any weather before hand with "The Weather Bug" app which tracks lightening in real time. If I sniff the ozone of a storm the system stays unplugged, as well as the computer. I'm playing chess that evening on my Chessnut, no music or movies for me!

@hifidream  - I'm curious.  What, if any, coax protection did you have at the time?  We had a significant near by strike here when I moved (2021 I think) that took out the cable provider's equipment and every single modem in my small subdivision.  I used an outdoor gas discharge protector.  While I did lose the modem, the Wifi router it was attached to and all the gear attached to it directly was not affected. 

My system was hit by lightening, it traveled through the coax cable line into my video processor via HDMI and then hit my projector. I had everything on quality surge protectors but it didn’t matter. The electrician I took the equipment to for insurance purposes said that lightening likes to have a path in and out so having things plugged into different wall outlets is an issue.

The electrician I took the equipment to for insurance purposes said that lightening likes to have a path in and out

@hifidream ,

I’m pretty sure he meant more than one earth connection to the electrical grounding system of the house. (From mother earth to the inside of the house and back out of the house to mother earth.)

All mother earth connections should be connected to the main electrical service equipment, service entrance neutral conductor that is bonded to the metal enclosure of the electrical service equipment. That especially includes the shield of the CATV providers coax cable. 

On the outside of your house just before where the coax cable enter your house there should be a grounding block. (sometimes the block is mounted in a plastic weather proof/resistant enclosure).

Here is where it can get tricky. How close is the grounding block from the outdoors electric meter socket enclosure? More than 20 feet?

If  20ft or less a minimum #14awg copper ground wire, (I would use #12awg solid copper minimum), install from the ground block lug to the grounding electrode conductor that come outdoors from the main electrical service equipment and connects to a ground rod(s) in the earth. (Some times the electrical service equipment is mounted outdoors beside the electric meter socket enclosure).

Use an electrical split bolt to connect the #12awg solid copper wire to the #6 bare solid copper wire,  (#6awg solid bare copper is the minimum size per code). (I prefer #4awg bare solid copper wire).

 Clean the bare #6 copper ground wire with a piece of emery cloth or fine sand paper.

Example of a split bolt. 

If distance from the grounding block to the grounding electrode conductor is greater than 20FT post back for instructions.

Grounding and Bonding of Communications Systems   

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I’m pretty sure he meant more than one earth connection to the electrical grounding system of the house. (From mother earth to the inside of the house and back out of the house to mother earth.)

Nope. 

Lightning strikes from coax or network connections aren’t necessarily from ground to ground.  They seek ground potential, but they are not necessarily carried in by the ground conductors. 

What the tech was referring to is that lightning potential seeks a path to ground, and will find the lowest insulated point to go through.  

This is a reason why I specifically do NOT recommend grounding Ethernet "surge protectors."  Best to deny a surge a path via isolators than to allow a low voltage current path which may also convert common mode to differential and enable the passing of a surge downstream. 

In the case of an outside surge coming in from other than the power lines, the series mode protectors have the edge as instead of encouraging the surge path they deny it, but only on the hot wire I believe.  

What the tech was referring to is that lightning potential seeks a path to ground, and will find the lowest insulated point to go through.  

Lightning is non discriminating. It will take any path that is provided to earth. The lower the soil to grounding electrode, (ground rod), resistance the better. Simple OHMS LAW.

Why give it two paths. In and out in the blink of an eye.

Let’s wait for @hifidream to respond to my post above. At this point we don’t know how the CATV grounding block is grounded. I can say if the CATV coax cable is on the opposite side of the house, than the electrical service is on, a ground stake was stuck in the earth and the grounding block was only connected to earth at the ground stake.  Lightning loves those type of grounding installations.  Lightning also loves audio isolated ground rods too.

Bonding communications systems

 

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I was living in a loft apartment at the time in the end unit of five in a row. I don’t know if the building was grounded properly. I did not have the coax going though a surge protector which probably was the issue as you describe. Of course the lightening went through the HDMI and fried my video processor, then projector and went out the wall through a surge protector which did not trip. So now all power runs through one plug via the P-15 and everything is streamed in 4K, it is all air gapped. Now I know for sure it’s safe, and I double check the Weather Bug every time I fire it up! The tech (30 year electrician and device repair man) was very clear, one path in for power and all connections or you risk creating a loop that encourages the lightening to travel around and exit after the damage is done. 

@hifidream said:

I was living in a loft apartment at the time in the end unit of five in a row. I don’t know if the building was grounded properly.

There is an unknown. A lot of variables. Age of the CATV coaxial cabling installation the biggest one.  

I did not have the coax going though a surge protector which probably was the issue as you describe.

Not a surge protector. A grounding block. Two different animals entirely.  

Example:

CATV coax cable shield Grounding Block

As you can see its pretty basic. But when installed properly it gets the job done diverting a near by lightning surge to earth and most importantly to earth using the  System Ground, Grounding Electrode System, of the electrical service of the building, dwelling unit. 

The lower the grounding electrode to soil resistance the better for diverting the high voltage surge to Mother Earth. Simple OHMS LAW... (Grounding Electrode? Ground rod(s) connected together. UFER  Ground,  foundation footing Concrete Encased steel rebar + Ground Rod(s) tied together creating ONE Grounding Electrode.)

The only true way to know what the soil to grounding electrode resistance is, is to have it measured by a person that is qualified.

NEC requirement for the soil to electrode resistance is pretty much useless. IF tested the soil to electrode resistance requirement is 25 ohms or less. IF higher than 25 ohms, then an additional ground rod is required. No further testing is needed. NEC code is satisfied. That’s why electricians drive two ground rods. No testing needed. Therefore no test documentation is needed  for the electrical inspector. A lot cheaper for the electrical contractor. Time is money...

( FWIW, IF tested the soil to ground rod may, for example, test 100 ohms. What are the odds driving a second 5/8" X 8ft rod will lower the resistance to 25 ohms or less?)

FWIW, IEEE recommends 5 ohms or less for a commercial electrical service’s grounding electrode.  

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The tech (30 year electrician and device repair man) was very clear, one path in for power and all connections or you risk creating a loop that encourages the lightening to travel around and exit after the damage is done. 

First I doubt he is a licensed electrician. He is more than likely just an electronic repair service tech. He may be very good at what he does. He is entitled to his opinions...

 Just a guess though for your experience at the time of losing  audio equipment from a lightning event was more likely from poor grounding of the shield of the CATV coax cable. Just curious, was you using more than one branch circuit to feed your audio equipment at the time? Or all of the equipment was fed from one branch circuit?

Jim

 

Welp, somehow things always get muddled.  For the record, I recommend the use of an outdoor coaxial surge protector mounted ON the grounding block. 

A grounding block is required for any coaxial cables entering a home from the outside, whether from the cable TV provider, an FM or TV or Dish antenna as well. These ensure the ground potential of your antennas stays at the same reference level as the rest of your home outlets so you don’t have the possibility that ground on your antenna is hundreds of volts different than the house ground.   This was probably installed by your cable/Internet provider already.  

A coaxial surge protector is there for cases when an electrical surge is present on the inner wire, diverting that excess voltage and current to ground before entering your home, which is why it’s best on the outside and on the grounding block itself.   They are imperfect but they do limit the fallout radius of a lightning surge.   Sometimes these are installed by the cable TV / Internet providers but usually inside on the modem. 

For further reading check out sites devoted to ham radio operators.  

If you have an antenna mounted in the attic a ground block is not required. 

@jea48 and @erik_squires 

Great suggestions but why create any risk at all? I literally have one wall plug for the entire system including the projector, content is streamed in 4K HDR wirelessly for movies, and same for music that isn’t on my server. 
 

Thanks,

Steve

@hifidream 

Wifi streaming is safest for your devices but may not be ideal depending on your neighbors and other factors.  My experience, as someone who not only streams but also needs a reliable network connection for work is that Ethernet is still the king of reliability.  If my PC or TV stop being able to stream I know it’s not my wifi. 

The use of a free wifi analyzer for your phone or tablet can always help you decide on the ideal configuration, not just in terms of signal strength but also picking out the least congested channels in your neighborhood as well as helping you decide where to put your router. 

Also, even if you opt for 100% wifi inside your home put your modem/router on a surge protector to reduce the chance of an incoming surge hitting your power lines and causing secondary damage through that path. 

@erik_squires Wi-Fi seems like a no brainer for lightening damage mitigation, which is what this topic is about. I have my computer hooked up to the network via CAT8 ethernet wire directly for day trading because latency could be an issue. I have never had a Wi-Fi outage or any issue related to Wi-Fi playing movies or music even with Wi-Fi 5 technology, which is up to 7 now. I live in a large apartment building in a signal dense neighborhood, there are over 30 networks to choose from when I search for one; I think interference is a thing of the past. I don’t want anyone scared to try this who may be in a lightening heavy area or simply wants the best way to secure their system based on assumptions. I unplug the computer from power and ethernet after each use, all three monitors including a 55” OLED are plugged into one surge protected distribution array with one plug into the wall. The router is on a surge protector. After experiencing the loss and time and effort to replace damaged equipment from lightening, the 10 seconds it takes to unplug everything is definitely worth my time and would encourage others to do the same. 
 

Thanks,

Steve 

I have never had a Wi-Fi outage or any issue related to Wi-Fi playing movies or music even with Wi-Fi 5 technology, which is up to 7 now. I live in a large apartment building in a signal dense neighborhood, there are over 30 networks to choose from when I search for one;

 

@hifidream  - Those are very good outcomes indeed!  I have been in similar situations and myself and my neighbors were constantly faced with Wifi buffering issues unless we actively attempted to find unused channels.

My advice is still the same, if in doubt at all use a Wifi Analyzer (free!) for your laptop or phone and look not just at signal strength but also channel congestion and try to pick out a channel with the least number of competing signals.  This by the way has also led me to discover that my Wifi router here at home was just spontaneously going offline.  Time for a new one. 

This is also an excellent tool to use to ensure your router placement was optional.  Did I mention they are free?  

@erik_squires Free is always best! 

I have a whole house surge protector on my external electric panel outside. It still won't protect against lightning strikes against the AT&t internet phone line. I'm working on getting a whole home search protector for the inner panel too.

 

Welp, somehow things always get muddled. 

How so? 

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FWIW...

NEC, Article 90

Quote:

90.1 Purpose

(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. This Code is not intended as a design specification or an instruction manual for untrained persons.

(B) Adequacy. 

(A) Covered. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance result in an installation that is essentially free from hazard but not necessary efficient, convenient, or adequate for good service or future expansion of electrical use.   

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"This Code is not intended as a design specification or an instruction manual for untrained persons."

Some people need to stop playing Electrician.

Roof top antennas and satellite dishes. An external signal power source is not at play, like a CATV or Internet only signal that is fed to a house by a coax cable signal provider company.

At the point , just before entry, into the house a grounding block is installed between the  CATV or Internet only providers coax cable. As I posted elsewhere in this thread NEC requires where it is connected, therein to the electrical service’s equipment GES, (Grounding Electrode System).  

Roof top antennas and satellite dishes  may use the same grounding block to bond the shield of the coax cable to the GES.  Language in NEC does not call it a grounding block though. Instead it is called a Discharge Unit. Google antenna discharge unit.They are not necessarily one in the same.  (FYI, the minimum size of the bonding ground wire required from the discharge Unit to the GES is #10AWG copper or 8 aluminum. NEC 810.21(H)). #10AWG copper wire, not to exceed 20ft in length... Is the #10 sized wire needed to discharge the static high voltage to Mother Earth or to divert a nearby lightning strike or lightning EMP high voltage transient surge to Mother Earth?  

(Food for thought. NEC only requires a #14 copper ground wire for bonding the grounding block to the GES for the shield of the coax cable for a  CATV or Internet only provider. FWIW the ampacity of an insulated #14AWG copper wire in free air is 35 amps.)

What are the differences between roof top antennas and satellite dishes and CATV or Internet only providers? For one the CATV or Internet only providers equipment is powered from a remote AC mains power system. Second is wind... Wind blowing across the surface of an antenna or a dish causes static electricity to build up on their surfaces.

( Static charge could be in the 1000s of volts) The Discharge Unit bleeds off the static charge to the GES, to Mother Earth. The Discharge unit also  will divert a nearby lightning high voltage transient surge to Mother Earth via way of the GES.

And yes bonding of the Discharge.Unit to the GES puts the shield of the coax cable at the same ground potential as the GES of the electrical service. That’s a given.

 As for this:.

A grounding block is required for any coaxial cables entering a home from the outside, whether from the cable TV provider, an FM or TV or Dish antenna as well. These ensure the ground potential of your antennas stays at the same reference level as the rest of your home outlets so you don’t have the possibility that ground on your antenna is hundreds of volts different than the house ground.   This was probably installed by your cable/Internet provider already.  

As for a  grounding block, used for the coax cable of a cable TV provider or internet only provider. Bonding the grounding block to the electrical service GES, is, hopefully*, at the same ground potential as the Grounding Electrode System, of the main electrical service equipment. (Reason it may not be? Poor and or corroded connections at each end of the bonding ground wire. Same for the F connectors connected to the grounding block.)  It does not guarantee there will not be a difference of potential from the EGC, (Equipment Grounding Conductor), at the wall outlet to the shield of the coax cable of the equipment it is connected to. Result, ground loop hum.  

*Reason for a difference of potential, voltage, from the shield of the coax cable  to the wall outlet EGC?  Resistance in the EGC connections from the wall outlet to the ground bar in the electrical panel due to poor and or corroded connections.. .If the wall outlet is fed from a sub panel add more connections because of the feeder EGC . Same problem can happen with the coax F connector connections as well).

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