Figure 1: Hydro workers work from boom buckets to restore power.
Power surge, also called transient overcurrent, is a short-term current and voltage fluctuation in the circuit, which usually lasts about one millionth of a second in the circuit.
In most countries, the typical voltage level for household appliances and electronic products is between 110 volts and 220 volts, while the average voltage in the United States is 120 volts. When the voltage entering the device through the wire increases significantly, this phenomenon is called a power surge. These power surges can be large or small, resulting in reduced performance of the plug-in devices or damage to them.
Power surge refers to an increase in "regular" voltage, usually caused by drastic changes or an increase in power demand. These actions, like turning on high-power appliances, vacuum cleaners, air conditioners, and washing machines, can all cause surges and peak voltages. Any type of interference can damage electronic equipment. In addition, inclement weather (lightning) and the daily shut-off and maintenance work of the power company will bring destructive surges to the power cord.
There are many reasons for power surges. The main reasons are electrical overload, wiring errors, lightning strikes, and the restoration of power supply after a power outage or blackout.
Figure 2: Many chargers are plugged in a socket.
When too much power is drawn from a single circuit, electrical overload may occur. The most common cause of this situation is excessive use of extension cords and too many devices plugged into the same circuit. After an electrical overload, power surges are common because an overwhelmed single circuit may receive a large amount of current and subsequent voltage spikes, which are drawn from the excess power.
Wiring errors are a potential internal cause of power surges, and damaged or exposed wires are more likely to make this happen. It may not be easy to see the problematic wiring, especially when it is installed in a wall.
However, there are other signs of wiring errors. These signs include burning marks in sockets, burning smells from wires or sockets, buzzing noises from sockets, and frequent tripping of circuit breakers. If these signs appear, please unplug all connected electrical equipment immediately and turn off the power of the area as fast as possible. If you suspect a wiring error, it is best to contact a certified electrician to check.
Figure 3: Lightning in the dark.
Lightning can cause serious damage by triggering electrical surges. Lightning damage is usually caused by directly hitting the power line, which generates a large voltage. When this happens, the electrical system could only accept excessive current and has no other choices. This can produce huge voltage spikes, which in turn can cause significant surges. Therefore, you should unplug any equipment that does not have surge protection during a major storm.
Power outages are usually caused by large-scale grid failures. Although a power outage usually does not cause any problems, the restoration of power supply after a power outage usually causes any problems. When power is restored after a power failure, it is common for the current to increase suddenly. Therefore, this kind of surge may damage any plug-in appliances and equipment that do not have a surge protector.
The following focuses on the analysis of the damage caused by the surge to the refrigerator and how to avoid it.
Figure 4: A young repairman is checking the refrigerator with a digital multimeter.
The refrigerator refrigeration system is a vapor compression refrigeration system, which is composed of the following components to form a closed system. The system is filled with refrigerant, which is driven by the compressor to circulate in the system pipeline. And it absorbs heat by the evaporator and releases heat by the condenser to achieve cooling function.
High voltage surge is one of the main causes of refrigerator damage. When the surge voltage rises, it will cause an inrush of current in the refrigerator. This surge generates excessive heat, which can damage many parts of the refrigerator. The three components that we often see damaged by high-pressure surges are the control panel, compressor and ice maker.
The control panel is the most sensitive part of the refrigerator. Therefore, when the surge current generates too much heat, it is easily damaged. Refrigerators with damaged control panels can usually be repaired because the control panels are relatively cheap and easy to replace by people themselves.
Figure 5: Condenser unit for cooling.
Although the compressor is not damaged as often as the control panel, it can also be damaged by powerful high-pressure surges. A strong current can damage the windings that provide the compressor's starting and operating functions, leading to premature compressor failure. If the compressor is damaged, sometimes it is better to replace the refrigerator because the cost of replacing the compressor is high.
If it is a refrigerator with an ice machine, the voltage surge can also damage the ice machine of the refrigerator. When an inrush of current causes additional heat to be generated in the component, it may cause a short circuit in the electrical connection of the ice maker. The replacement cost of ice maker components is relatively low, and if parts are available, refrigerators with this type of damage can usually be repaired.
There are many ways to prevent damage from power surges. By ensuring that your equipment does not overload the circuit, you can prevent internal surges. Note that large electrical appliances for example air conditioners should not share the same socket with other electrical appliances, and ensure that the wiring conforms to the specifications.
Although external power surges are sometimes unavoidable, you can still prevent damage to equipment and appliances by unplugging them during major storms.
Figure 6: Unplugging electrical cords.
You can also use surge protectors for your appliances and gadgets. First plug the surge protector into the wall outlet, and then plug the refrigerator into the surge protector. If a power surge occurs, a surge protector will help prevent electrical damage to the refrigerator. It can prevent excess voltage from reaching your electronic equipment in the event of a power surge.
However, the only way to absolutely protect your refrigerator from power surges is to unplug it completely. Many power surges happen randomly, but if you know that a thunderstorm is coming, you can unplug your electrical appliances as an extra precaution. Once the threat has passed, just plug it in again.