Why do home appliances break after thunder?
Every summer during afternoon thunderstorms or typhoons, someone’s home appliances will always win the lottery. The TV won't turn on, the air conditioner circuit board is burned out, the router is broken... these seemingly unrelated problems may all have the same culprit behind them: lightning surges.
Many people will wonder: "My building has a lightning rod, why do home appliances still break down?" This is because the protection range of lightning rods is limited. It can only protect the building body from direct lightning damage, but it cannot prevent the surge caused by lightning strikes from entering the room through power lines and network cables.
What is lightning surge?
When a lightning strike occurs, whether it hits a building directly or falls nearby, an extremely high voltage pulse will be generated in an instant. This is the so-called "Surge".
How do surges occur?
According to Taipower, a lightning strike will generate a strong electromagnetic field around the lightning strike point. This electromagnetic field will induce high voltage on nearby metal wires (such as power lines, telephone lines, Internet lines, and cable TV lines).
Although this induced voltage is not as strong as a direct lightning strike, it can still reach thousands of volts or even tens of thousands of volts, far exceeding the tolerance range of ordinary household appliances (usually only a few hundred volts).
Surge wave propagation path
Surge waves will be transmitted into the home along various metal wires. The main paths include:
- Power cord: From the outdoor power system through the distribution box to the indoor socket.
- Network cable: If the outdoor network cable is struck by lightning, the surge will be transmitted along the network cable to the router and computer.
- Cable TV cable: Coaxial cable is also the way in which surge waves are introduced.
- Telephone lines: Traditional phone lines can also introduce surges.
This is why sometimes even though lightning does not hit your home directly, the electrical appliances in your home will still be damaged. Because the surge is "transmitted" through various pipelines.
Surge damage to home appliances
Surge damage to home appliances can be divided into two types:
Immediate damage
If the surge voltage is extremely high, the electronic components of the home appliance will be burned instantly. In this case, the appliance will immediately malfunction and become unable to turn on or operate.
Common damaged components include:
- Fuses and capacitors of power supply
- IC chips on the motherboard
- Compressor circuit board
- LED TV backlight driver board
This kind of damage is usually obvious and can be known at the first try.
Cumulative damage
What is more troublesome is cumulative damage. Although each surge does not burn the components immediately, it will cause slight damage to the electronic components. Over time, component performance gradually degrades, eventually leading to failure.
This kind of damage is difficult to detect. It may occur after one or two years of use. Consumers often do not know that the problem is caused by sudden surges.
Why can’t lightning rods protect home appliances?
This is a myth that many people have. Lightning rods (the correct name should be "lightning arrester" or "air terminal") are designed to protect the building structure and prevent direct lightning strikes from causing fire or structural damage.
Operation principle of lightning rod
Lightning rod guides lightning current to the grounding system through the principle of tip discharge, and then releases it to the earth. This protects the building itself from being struck by lightning.
Limitations of lightning rods
But the problem is that lightning rods can only deal with "direct lightning strikes" and are powerless against "induced surges" generated by lightning strikes.
When lightning strikes nearby, the electromagnetic field generated will induce surges in various pipelines. These surges will be transmitted into the room along the pipeline, and the lightning rod cannot control it at all.
To put it simply, the lightning rod protects the "house", not the "electrical appliances in the house".
Surge Protector: The Patron Saint of Home Appliances
To protect home appliances from surge damage, a special "Surge Protection Device" (SPD) needs to be installed.
The operating principle of the surge protector
The principle of the surge protector is very simple: when the voltage on the line is normal, it will have no effect; but when an abnormally high voltage (surge) is detected, it will conduct in a very short time (nanosecond level) to guide the surge current to the grounding system and protect the back-end equipment.
You can think of it like the spillway of a reservoir: the reservoir normally stores water, but when a flood comes, the spillway will automatically open to drain excess water and protect the reservoir dam from being washed away.
Types of surge protectors
According to the installation location and function, surge protectors can be divided into several types:
Type I (Type I): Total protection
Installed at the main distribution box of the building to protect large surges generated by direct lightning strikes or close-range lightning strikes. This type of protector is typically used in commercial buildings or critical facilities.
Type II: distribution protection
Installed in the floor distribution box or in front of important equipment to protect against remaining surges. This is the most commonly used type in general households.
Type III: End protection
It is the common "lightning protection plug" or "surge protection socket", which is installed at the front end of electrical equipment to provide the last line of defense.
The concept of multi-layer protection
Complete surge protection should be multi-layered: the first type of protector intercepts most of the surge energy in the main distribution box, the second type of protector in the floor distribution box for further protection, and the third type of protector provides the final line of defense at the front end of the equipment.
Only by checking at all levels can the safety of home appliances be ensured.
Practical suggestions for household surge protection
For ordinary households, the following are practical suggestions for surge protection:
Check the grounding system
For surge protectors to operate effectively, they must have a good grounding system. If the building is not grounded or has poor grounding, the surge protector cannot guide the surge current to the earth and is useless.
You can ask a qualified electrician to check the grounding system in your home to confirm whether the grounding resistance meets the specifications (generally required to be below 100 ohms).
If it is an old house, it may not have a grounding wire. It is recommended to improve it during decoration. This money cannot be saved, otherwise it will be useless even if the surge protector is installed.
Install a surge protector in the distribution box
It is recommended to install a second type of surge protector in the main distribution box to protect electrical equipment throughout the house. This type of protector costs about a few thousand yuan and should be installed by a professional electrician.
When installing, pay attention to selecting qualified products and confirm whether the specifications meet the requirements. Don’t buy cheap products from unknown sources, otherwise they may not provide effective protection.
Use surge protection sockets
For important equipment, such as computers, TVs, stereos, etc., it is recommended to use surge protection sockets. These sockets have built-in surge protection components to provide additional protection.
When purchasing, be sure to choose certified products, such as UL, CE and other international certifications. Cheap knock-off products may only have an outer shell like a surge protector, with no protective components inside at all.
Network cables and antennas must also be protected
Surges are not only transmitted from power lines, but also network cables and cable TV antennas. If routers and TVs are often damaged by lightning, consider installing surge protectors on these lines.
There are surge protectors on the market specifically for network lines and coaxial cables, which can be installed where the lines enter the room.
Protection measures for home appliances in extreme weather
In addition to installing surge protectors, some temporary measures can also be taken when extreme weather strikes:
Before a lightning strike
If the weather forecast shows that there will be strong lightning strikes, the following measures can be taken in advance:
- Unplug important electrical appliances, such as computers, TVs, air conditioners, etc.
- Unplug the Internet cable and cable TV cable.
- Turn off unnecessary power to reduce the risk of damage.
This is the safest approach. Although it is troublesome, it can completely avoid sudden wave damage.
When a lightning strike occurs
If a lightning strike occurs while using an electrical appliance, pay attention immediately after hearing the thunder:
- Observe whether there are any abnormalities in the electrical appliance, such as smoke, odor, and abnormal sounds.
- If there is any abnormality, turn off the power immediately and unplug it.
- Do not touch metal objects that may be electrically charged.
After a lightning strike
After a lightning strike, check whether the electrical appliances in your home are normal. If you find an electrical fault, do not use it forcefully and ask a professional to check it.
In addition, check whether the surge protector has been activated. Some surge protectors have indicator lights that will display after activation. At this time, the protector needs to be replaced.
Maintenance and replacement of surge protector
Surge protector is not installed once and for all, it also has a lifespan.
Life of a surge protector
Every time a surge protector operates, the internal protection element (usually an MOV, metal oxide varistor) is slightly damaged. As the number of movements increases, the protective ability will gradually decrease.
Generally speaking, the lifespan of a surge protector is about 5-10 years, but if surges are encountered frequently, the lifespan will be shortened.
How to determine whether it needs to be replaced?
More advanced surge protectors will have indicator lights to show the protection status. If the indicator light goes out or changes color, it means the protector has failed and needs to be replaced.
If there is no indicator light, it is recommended to ask an electrician to check it regularly, or replace it according to the original manufacturer's recommended period.
Don’t save this money
Some people think surge protectors are expensive and are unwilling to install them. But please do the math: a high-end TV may cost tens of thousands of yuan, and a computer may cost tens of thousands. If it is damaged by lightning, the loss will far exceed the cost of the surge protector.
What's more, some damage is cumulative, and it may take a year or two before it breaks down. By then, you don't know it was caused by a surge, and you think it's a product quality problem.
New thinking on surge protection under climate change
With climate change, extreme weather becomes more and more frequent, and lightning strike activity may also increase. According to research, rising temperatures will increase atmospheric instability, leading to more frequent thunderstorm activity.
Under this trend, surge protection is no longer an “optional” option, but a necessary investment for home safety.
Standard equipment for new houses
Surge protectors should be listed as standard equipment for new houses in the future, just like leakage circuit breakers, which are basic safety requirements.
Opportunities for improvement in old houses
If an old house is being renovated or renovated, it is recommended to take the opportunity to install a surge protector. At this time, the distribution box has been opened and the installation cost is relatively low.
Protection needs of smart homes
Modern homes have more and more smart devices, such as smart speakers, smart light bulbs, smart home appliances, etc. These devices have sophisticated electronic components inside and are more sensitive to surges.
While enjoying the convenience of smart life, don’t forget to take surge protection, otherwise these expensive equipment may be wiped out due to a lightning strike.
Conclusion: nip in the bud
Lightning surge is an invisible threat, but the damage caused is real. Rather than regretting it later, it’s better to take precautions beforehand.
Install surge protectors, check the grounding system, and unplug during extreme weather. These simple actions can protect your expensive home appliances and avoid unnecessary losses.
Climate change has made extreme weather the norm, and our home protection must also keep pace with the times. Don’t let a lightning strike destroy the home appliances you have worked so hard to save.
New knowledge on air-conditioning power consumption and Taiwan climate maintenance regulations in recent years (2025-2026 current situation)
With the high temperatures in summer breaking historical records and the adjustment of electricity price structure in recent years, the latest statistics from the Energy Administration of the Ministry of Economic Affairs show that air-conditioning equipment accounts for more than 47% of residential electricity consumption in summer. Many people mistakenly believe that if the air conditioner is not cold, they only need to "replenish the refrigerant." However, in fact, refrigerant is not naturally consumed during normal operation in a closed circuit. If the refrigerant is insufficient, it means that there are micro leaks in the copper pipes or joints. Simply replenishing the air conditioner will only treat the symptoms but not the root cause. Refrigerant leakage will aggravate the high temperature overload of the compressor and shorten its service life.
According to Taiwan's standard operating specifications for air-conditioning projects, it is recommended that professional technicians with a refrigeration and air-conditioning decoration technician license perform "full machine high-pressure water washing and evaporator deep sterilization" every 1 to 2 years for detached air-conditioning indoor units. Especially in the humid summer in the Shuangbei Basin, the air drum and water collection tray are easy to breed black mold and jelly-like biofilm. This is also the main reason for the sour smell in the air-conditioning outlet and the backflow of the drainage pipe. Regular maintenance can maintain CSPF (Air Conditioning Seasonal Performance Factor) level one energy efficiency level, which can save an average household 15% to 20% of air conditioning electricity bills every year.
Autonomous simple maintenance vs professional maintenance safety red line
- Homeowners can do by themselves: Remove and clean the nylon filter regularly every 2 to 3 weeks (rinse with clean water and dry in a cool place, do not expose it to the sun to avoid deformation and embrittlement); clean the air outlet blades of the indoor unit with a dry cloth; check whether there is any accumulation of debris within 50 cm around the outdoor unit that hinders heat dissipation.
- Professional technicians must be entrusted according to regulations: Refrigerant pressure testing and leakage repair welding, high-pressure cleaning of indoor unit air drums and aluminum fins with liquid chemicals, reset of the drainage slope of hidden cold water pipes in the ceiling, and 220V dedicated power circuit configuration and leakage circuit breaker replacement.
