Since my daily activity of choice is to help folks locally with their computer gremlins I get to see and hear about plenty of unfortunate computers that have met their end as a result of surges. You see, in my neck of the woods we battle power surges frequently.

All devices, computers being no exception, have a specific power spec that they are designed to operate on. When more power is forced through a device than what it is designed to handle, it can result in damage to its internals. More specifically, the oversupply of power can create an arc of current inside the device. This arc produces heat which causes damage to the circuitry. Devices with microprocessors, like computers, are particularly sensitive to electrical disturbances.

While the answer to this question may seem obvious, I thought it would still be great to explore the topic. It may be helpful to know that not all power surge related gremlins are ultimately fatal, sometimes the fix is pretty simple! There are also things you can do avoid these gremlins.

I’ll cover the following in this article:

  • The how and why – Power surges, spikes, brownouts and outages and their effects on computers
  • Ways to prevent power surge damage
  • Basic troubleshooting tips – easy steps you can follow straight away if your computer is “playing dead”.

How can power-surges affect computers?

First let’s think about what a power-surge actually is.

A power surge or power spike is a momentary oversupply of power. Even just a few nanoseconds of an oversupply can leave devices inoperable.

The result?

Of course the worst that can happen is a totally dead computer (and maybe some ‘fireworks’ to go with it…)

Some possible tell-tale signs that the power surge gremlin has struck:

  • When you turn the computer on you can hear the fans spinning but the screen stays black
  • The computer turns on but is stuck in a constant reboot loop
  • Laptop won’t charge / battery won’t hold a charge
  • The computer won’t turn on at all and appears completely dead

What causes power surges?

Power outages

It is important to understand that power-surges often go hand-in-hand with power-outages.

We experience a lot of power-outages where I live. While a sudden power-cut to a computer isn’t so bad, surges often happen when the electricity comes back on. When restored, the supply from the grid can cause a surge of power.

What makes it worse is that you won’t even know that a surge has hit your device until the unpleasant symptoms present. .


This is a mean one. You don’t want your computer playing chicken with a lighting strike.

One hit of lightning can produce thousands of volts. Even if it doesn’t hit your house directly it can travel along the supply to your house and sizzle your devices.

Lightning isn’t fussy either. It doesn’t only choose the electrical supply to enter a building, it can also travel along phone, internet and network cables.

Standard operations of utility companies

From time to time the power utility company may switch grids. This is part of normal operation and usually happens when they need to clear a fault in the line. Clearing a fault often involves changing to another supply or interrupting the flow of electricity temporarily. They also switch grids sometimes when they need to make changes in the allocation of power to users. Grid switching can cause disturbances in the supply of electricity that can result in power surges.

Surges and dips that result from utility grid switching and large appliances kicking in regularly often go unnoticed as it is not always apparent. This is silent and sneaky kind of damage because consistent hits degrade your devices over time.


If you have too many devices plugged in and running off a line it can cause an electrical overload. An overload is when there are too many devices pulling power from a circuit. It can also happen if a single device draws more amps than the circuit can supply. When an overload happens it can cause a temporary surge of power before (hopefully) the breaker trips.

Faulty Wiring

If you find that your fuses are always blowing or that your breakers are constantly tripping this could be a sign of faulty or inadequate wiring. Keep in mind that wiring in older homes & buildings isn’t designed to accommodate large capacity appliances.

Anything that disturbs the flow of electricity, such as degraded or inadequate wiring can cause surges. It may be time to have your wiring checked out by the pros to make sure everything is in order.

Power-hungry appliances on the line

Appliances that have motors that kick in every so often can be quite power hungry. Think appliances like fridges, air conditioners and compressors. Because they draw a lot of power when their motors kick in, it can cause disturbances on the line and you guessed it – it can result in a power surge.

Can you prevent damage caused by power surges?

Fortunately there are some things we can do to protect our computers from surge damage. How effective the solution is depends on how powerful the surge is.

Did you know? – Even if your device is turned off and the switch is turned off by the power outlet it can still be zapped by a power surge. So long as it is plugged into a power outlet, it is in the ‘hot seat’.

– Unplug

The FREE but somewhat impractical way to avoid power surge damage is to immediately unplug your computer or laptop from the power source when you experience a power outage and also when there is lightning/thunder. When power is restored after an outage, wait around 15 minutes before hooking everything back up as it gives the utility power grid time to stabilize.

– Handy gadgets

As busy humans, we may not always be able to unplug everything when we need to and so that’s why I hook my computer equipment up to a UPS (uninterruptible power supply). For extra measure, my UPS is connected to the power outlet via a good quality surge protector.

While the main purpose of a UPS is to give you some time to shut down your computer properly when there is a power outage, it also helps to regulate the power being supplied to your computer. Most of them also have built-in over voltage protection.

If you add a surge protector plug into the mix, it should take the blow before it gets to your UPS. Be sure to look for a surge protector that actually stops supplying power to your devices when it can no longer protect them, like the Tripp Lite TLP1208TELTV. Most cheap ones keep supplying power without the protective function, giving a false sense of security.

NB! Surge protectors & lightning – even with a super high quality surge protector that can take a massive hit, I wouldn’t bank on it to protect my computer. I always unplug my goodies during lightning storms.

– Defend & Maintain

Your first line of defense against lightning should be whole-house protection. Whole house protection helps absorb and route the powerful volts of electricity away from your home via the path of least resistance back into the ground. It also involves the tripping of breakers before the surge can get to your plugged-in devices.

Having your building’s wiring checked out & maintained by a professional, especially if it is a very old building, will help prevent surges that result from faulty wiring.

Check that you aren’t overloading (having too many power hungry appliances working on the same line).

Troubleshooting Tips

If it is too late and your computer has already been zapped, you can try this basic troubleshooting process. Luckily the chances are good that you can get things up and running again – or at least just enough to salvage your data.

Basic/Beginners Troubleshooting (Laptop or Desktop Steps 1 to 8)

This process drains all residual power from the computer, since anything that may have shorted out inside could be preventing it from turning back on.

Step 1 – Unplug the power cord or laptop charger completely

Step 2 – Unplug all storage devices such as hard drives and flash drives

Step 3 – If it is a laptop, remove the battery (newer laptops do not have removable batteries – if you’re forced to skip this step this process may not work, you will have to get inside your laptop to disconnect the battery which can be tricky – take it into a repair shop for assistance)

Step 4 – Hold the power button in for at least 60 seconds (count, trust me, don’t rush this step)

Step 5 – Plug the battery back in, plug the power cord back in

Step 6 – Turn the computer or laptop on as usual and cross fingers

    If it still doesn’t work:

    Step 7 – Try using another power outlet and/or power strip

    Step 8 – Try another power cord/charging adapter, the zap could have sizzled the cord

    Laptops only

    Step 9 – Laptops only – remove the battery and try to power it up directly via AC (charging adapter cord) – the battery may be faulty

    Advanced – Desktops only (Steps 10 to 16) :

    Step 10 – Unplug all power, drain power by hold down the power button for 10 seconds

    Step 11 – Open the case, keep yourself grounded throughout fiddling by keeping contact with the power supply or using an anti-static wrist band (static electricity may zap your components)

    Step 12 – Remove the CMOS battery, hold down the power button for 60 seconds, re-insert it and test again

    – If your computer doesn’t turn on at all:

    Step 13 – test by replacing the power supply unit with a spare or borrowed working one (I don’t recommend buying new parts until you’ve pinpointed the problem)

    Step 14 – Check that your CPU fan is spinning when you turn on the desktop, some computers will not turn on if the fan is not working. Others will turn on but shut off soon after due to overheating. Try plugging it into a different header if the CPU fan isn’t working. It will need to be replaced if it isn’t working.

    – If your computer turns on but shows a blank screen:

    Step 15 – By process or elimination, unplug one component at a time. Start with the RAM modules (remember to try different RAM slots as well). Then the optical drive, the hard drive and the graphics card (remember to use the on-board video output port to plug in the monitor after removing the GPU),

    Finally, try re-seating the processor – remember to reapply thermal paste if you do this (be very careful as you can break the CPU cooler clips or bend the CPU pins accidentally when you fiddle with those parts).

    Step 16 – Power on the machine after unplugging a component to test – observe results.

    NB. Remember to turn off and discharge your computer before touching component inside the case!

    If you’ve gotten this far and still no luck it is likely the motherboard and/or CPU that needs replacing. If you can’t get the same specification of motherboard, you will need to probably replace the CPU and RAM with compatible parts.

    If the idea of fiddling inside your computer is scary and you don’t want to risk further damage, a computer repair shop will be able to do all these advanced testing steps for you. They will likely also have compatible parts lying around to test with.

    Note that you may still be able to get your data recovered as the hard drive might still be intact! Ask the techs to check that for you.

    The Take-Away

    Power surges can definitely wreak havoc on computers but there are simple ways to avoid them.

    Prevention is better than cure for sure as tech support and replacing certain parts can be an expensive exercise .

    Luckily, basic troubleshooting is simple enough and often effective!

    For more advanced gremlins a techy should be able to help you bring your computer back to life and recover your data relatively painlessly.


    I want to hear from you! Ever had a power surge? Share your story below 😀

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