lightning storm


listening to my new Maria Callas vinyl last night and a huge thunderstorm/lightning storm starts up. About 2,3 seconds before each boom, I was getting a lot of static through my speakers. EMI from the lightning? I have no idea so asking the group. Thanks. Smart ass answers accepted also :-)

dmk_calgary

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.