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Surge Protector Lightning Strike Protection: Computer & Modem Safety During Storms

Damian. 66475 34
Best answers

Will a surge protector keep my computer and modem safe from lightning during a storm?

No, a surge strip alone will not reliably protect a computer or modem from a lightning strike; it mainly handles smaller surges and induced overvoltage, not lightning energy [#4174620][#6754431] The strip is only the last stage of a multistage protection system, while the real lightning discharge is meant to be handled upstream by A/B/C arresters in the installation [#4174620][#4245513] People in the thread reported burnt PSUs, routers, modems, and other devices after storms even when using strips and grounding, so a direct or nearby strike can still cause damage [#4174444][#4245114][#4174517] The safest practical step is exactly what you already do: unplug the mains and disconnect the modem/telephone/network cables during storms [#4174444][#4174517] A strip can still help against everyday transients, but it is not a substitute for proper whole-system surge protection or physical disconnection [#4174620][#4245513]
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Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
  • #31 6761198
    KaW
    Level 34  
    1-half of this damage can be avoided by applying the correct rules
    execution of all leads / and distribution / electric -
    mainly energetic - the house, building, etc.
    2-Americans in simple sketches of installations entering the house
    - on the wires / from the outside / they make such a few turns with the Cu wire and ground / lead to the nearest earth electrode /. The nearest - means making the earth electrode just below the place of introduction.
    If only every cable coming from the outside had such a design
    the inside of the house would be safer.
    The 3-socket power strip of the equipment is pointless, they duplicate what is already in the equipment
    there is security in power supplies. They are dangerous themselves - because
    The power switch can burn - and sometimes the clasps fall off
    metal - inside - make a short circuit.
    4-in the case when the only expense for overvoltage protection - is about PLN 50 for a "surge voltage" strip - the results will be
    unhappy.
    5-unfortunately, overvoltage protection is not cheap in practical implementation, but you can slowly increase its level by collecting materials such as: how and what to do to make the overvoltage protection better and implement your plans step by step.
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  • #32 6761341
    Lazer
    Level 24  
    vcc wrote:
    I saw the UPS after the lightning meeting - a pile of coal in the housing, and the computer survived, and the power supply in it, so there is some protection.

    Probably the only and best security. After the shot, it will only seduce the UPS, but it is not a rule to follow. In my case, the old APC-600 has always been in front of computer hardware. It once struck a central hit on the street and smashed the UPS, not to mention how beautifully a 60W / 240V light bulb fired in the kitchen on the ceiling with sumptuous fireworks from the sockets. Amazing view but no wonder. The equipment withstood, and in the UPS the fuses, varistors and 8 transistors or sometimes some small things for good measure fell out. After the repair, he got a new life :) and this is already his 3.
    At home, a 3-wire single-phase electrical installation, as in the old building, without a lightning protection system, but I just drove a 2m long steel loop into the ground and connected the pins from the sockets to it, because the washing machine "ligated" and after this treatment it stopped :D
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  • #33 6761941
    Pokrentz
    Level 22  
    @OldSkull: Somehow I can't remember anything too ordinary lucko [it's about a transformer ??] it fell. Probably nothing. There were contraptions behind the impulse power supplies (first, the power supplies themselves). Now, at the lightest sound of the storm, I practically turn off the electricity in the cottage. Fuses and some I2C memory cube fell in the CO furnace.
    One lightning bolt in the pole cost me some 2 kPLN and it will still cost a new monitor (I'm now on a borrowed one).
    I wonder if it would be possible to resuscitate this with burnt backlight. If I had the so-called a graphoscope, I would do a home theater, and yes, just remove the casing from the back and put a candle behind the monitor ...


    [On the forum we use the Polish font and the adopted spelling rules. Please correct the post. Mariusz Ch.]
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  • #34 6763495
    mrowaa
    Level 15  
    Hello!
    Earlier I was supposed to write but it was closed ..
    Can I feel safe if I turn off the main circuit breaker during a storm? It seems to me that not because why the spark would not jump.
    The second thing is if something hits the rope and goes to the house along the wires in the wall: do I have to replace the installation then?
    And another kind of thing: I have radio internet. If the discharge goes along the antenna cable to the router, can it get to the electrical network at home?
  • #35 21592550
    Patryk79123
    Level 5  
    Ancient records from many years ago.

Topic summary

✨ Surge protectors, especially power strips with varistors (type D protection), provide limited defense against lightning strikes and are primarily effective against induced overvoltages or minor surges rather than direct lightning impulses. Comprehensive lightning protection requires a multi-stage system including type A (pole-mounted), B (building connection), and C (fuse box) arresters to progressively reduce voltage and current levels. Direct lightning strikes generate extremely high voltages (hundreds of thousands of volts) and currents (tens to hundreds of kiloamperes), which typically exceed the capacity of common surge protectors and fuses, often resulting in damage to connected equipment despite protection attempts. Devices powered by transformers tend to be more resilient due to their inherent electrical inertia compared to semiconductor-based switched-mode power supplies, which are more vulnerable. Isolation transformers (230V/230V) can offer better protection by galvanic isolation but may still be damaged by strong surges. Disconnecting equipment from power and communication lines during storms remains the most reliable method to prevent damage. Proper grounding and installation of surge protection devices are critical; poor or absent grounding significantly reduces protection effectiveness. Lightning can also enter through antenna or telephone lines, necessitating protection on these lines as well. Some surge protectors are disposable and costly, and their effectiveness depends on correct installation within a coordinated protection system. Insurance may be a practical consideration given the limitations of surge protection devices. Overall, no single device can guarantee full protection against direct lightning strikes, and a layered approach combined with prudent disconnection practices is recommended.
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FAQ

TL;DR: Average lightning carries 30–50 kA current [Wikipedia, Lightning]; “the strip is only an element of the surge protection system” [Elektroda, William Bonawentura, post #4174620] A lone power-strip varistor can’t absorb that energy. Multi-stage arresters plus unplugging give the highest survival odds.

Why it matters: One missed plug or data cable can destroy a PC, router, and TV in microseconds.

Who this helps: Home users and small-office owners looking for practical, budget-aware lightning and surge protection.

Quick Facts

• Direct-strike peak current: 30 kA–200 kA; average 30 kA–50 kA [Wikipedia, Lightning] • IEC 62305 target after Type D stage: ≤1 kV residual voltage IEC 62305 • Type C DIN-rail surge module price: approx. 100 PLN / €22 [Elektroda, William Bonawentura, post #4174620] • Varistor strips are single-use; devices often “explode” after one hit [Elektroda, stasiekm, post #4245513] • 230 V/230 V isolation transformer adds ~1 kV galvanic isolation [Elektroda, RPG, post #4176185]

Will a cheap surge-protector strip save my PC from a direct lightning strike?

No. A strip is Type D protection, the last and weakest stage. Alone it can only clip small induced surges. William Bonawentura notes it “is not able to seize and suppress lightning energy” [Elektroda, 4174620] For a direct line hit, energy exceeds the varistors’ capacity and both strip and equipment burn.

What’s the difference between Type A, B, C and D surge arresters?

  1. Type A (pole) spark gaps carry several-thousand-amp currents but let kilovolts through.
  2. Type B (service entrance) handles hundreds of amps, clamps to a few kV.
  3. Type C (consumer panel) takes tens of amps, clamps below 1.5 kV.
  4. Type D (socket strip/UPS) handles amps, trims to sub-kilovolt levels [Elektroda, William Bonawentura, post #4174620] Cascading reduces voltage step by step.

Does physically unplugging equipment really work?

Yes. Removing all power, coax, and phone leads breaks the conductive path. Users report zero damage only when plugs were out [Elektroda, Damian., post #4175766] It costs nothing and beats any single-device protector.

How much energy does a lightning bolt deliver?

A typical stroke releases about 140 kWh, equal to a month of household electricity for a 5 kW load [Wikipedia, Lightning]. Even the fastest varistor fails long before absorbing that energy—an edge-case many homeowners overlook.

Why do switch-mode power supplies die more often than transformer units?

SMPS front-end semiconductors react in nanoseconds; over-voltage punches through before fuses blow. Shanleaf lost four SMPS chargers while transformer units survived the same storm [Elektroda, 4174517] Transformers add leakage inductance that slows the surge.

Can a UPS absorb a lightning surge?

A UPS may sacrificially fail, saving downstream gear. vcc saw a “pile of coal” UPS while the PC lived [Elektroda, 4174730] Still, the UPS is only Type D; a close strike can jump its isolation gap.

How do I protect my modem, router and network lines?

  1. Add RJ11/RJ45 coaxial gas discharge or MOSFET arresters at the entry point.
  2. Bond cable shields to the same earth bar as power arresters.
  3. During storms, unplug both power and data leads; zdzislaw111 lost a TV through a grounded cable line alone [Elektroda, 4245114]

What’s a cost-effective multi-stage setup for a house?

• Install a Type B combination arrester at the main breaker (~500 PLN). • Snap-in Type C module in the apartment panel (~100 PLN) [Elektroda, 4174620] • Use a quality strip with thermal-fuse varistors near electronics (~120 PLN). Total under €175 protects most surges; unplugging still advised for storms.

Will an isolation transformer stop lightning-induced surges?

It helps with common-mode spikes up to its insulation rating (~1 kV), but a direct or nearby strike can arc across windings. RPG recommended 230 V/230 V transformers as added safety, not a complete solution [Elektroda, 4176185]

Does proper grounding really reduce damage?

Yes. Lower earth resistance (<5 Ω per IEC 62305) gives surge arresters a low-impedance path. Dipol notes that without good grounding “all protections are just decoration” [Elektroda, 6756435] Poor or absent grounds let destructive voltage rise inside.

Can surges travel through coax or Ethernet even if the power is off?

Yes. High voltage needs only a few centimeters of insulation to arc. zdzislaw111’s unplugged TV burned through its PCB via the cable line [Elektroda, 4245114] Always disconnect signal cables or fit line arresters.

How do I safely shut down during a storm?

  1. Power off devices, then pull mains, antenna, and phone plugs.
  2. Move cables 30 cm away to avoid flashover.
  3. Wait 10 minutes after the last thunderclap before reconnecting. This follows field practice shared by multiple forum users [Elektroda, 6751649]

Are “lightning-proof” PLN 120 premium strips worth it?

Only if they house real gas discharge tubes plus thermal-fuse varistors. Anonymous linked Vivanco strips that include such parts, unlike budget models [Elektroda, 4176316] Verify internal components and warranty terms before paying the premium.

Is insurance cheaper than hardware protection?

Forestx chose household insurance; his insurer covered a TV lost to lightning [Elektroda, 6757951] Annual premiums (~150 PLN) rival the cost of one quality Type C arrester. Combining both spreads risk: hardware cuts outages, insurance covers catastrophic loss.
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