Nina Raemont/ZDNET
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**ZDNET’s key takeaways—expanded for clarity and detail:**
Heavy-duty household appliances, when improperly connected, can easily exceed the electrical capacity of standard cords, causing excessive current flow that leads to dangerous overheating and an increased risk of electrical fires. Any device drawing more than 1,800 watts of power should always have its own dedicated wall outlet to ensure proper energy distribution and to minimize hazard. Furthermore, connecting multiple extension cords together—commonly referred to as daisy-chaining—is an especially unsafe practice that can multiply resistance and heat generation along the length of the circuit, significantly increasing the likelihood of fire.

Extension cords are undeniably convenient, often serving as temporary solutions for powering devices located far from built-in wall outlets. However, this practicality has limits. A crucial but frequently overlooked difference exists between relatively low-power electronics—such as laptops or chargers—and high-power home appliances like microwaves or space heaters. While both technically qualify as electrical devices, high-draw appliances require a substantially greater current to operate efficiently. When these power-demanding machines are connected to inadequate cords, the wire insulation and internal components can heat up rapidly, transforming what was intended as a simple solution into a major safety threat.

**Understanding why not all devices belong on extension cords:**
An extension cord’s design directly determines its capacity to carry electrical current safely. That capacity depends largely on the thickness—or gauge—of the wiring inside. For comparison, a 16-gauge cord is capable of managing up to approximately 13 amps, whereas a sturdier 14-gauge version supports up to 15 amps, equivalent to about 1,800 watts—the same limit as most standard residential wall outlets in the United States. If an appliance attempts to pull more power than the cord is rated to deliver, the cord can quickly become overloaded. Over time or even within minutes, this overload can cause the cord’s insulation to degrade or melt, exposing live copper wiring and dramatically heightening the risk of electric shock or open flame ignition.

As a general rule, any household appliance that requires more than 1,800 watts should never be powered through an extension cord and should instead be supplied by a dedicated electrical circuit. Below are seven common household devices that must always be connected directly into a wall outlet for both performance stability and safety.

**1. Refrigerators**
While a refrigerator lacks an overt heating element and tends to use less wattage in one moment than active cooking devices, its compressor runs continuously, drawing substantial cumulative power. Even though the immediate risk of fire is moderate compared with other appliances, plugging a refrigerator into an extension cord can cause voltage drops that interfere with the compressor’s operation, potentially leading to malfunction or complete breakdown. Keeping it directly connected to a grounded outlet ensures consistent current and long-term reliability.

**2. Toasters and toaster ovens**
Compact yet deceptively powerful, toasters require a robust energy supply to produce the heat necessary for browning bread. Toaster ovens, which perform additional baking and reheating tasks, consume even greater wattage—typically ranging between 1,200 and 1,400 watts. When these appliances are connected through an extension cord, the elevated current load can overheat both the plug and sockets, making them a recognized fire hazard. Plugging them straight into a dedicated wall outlet ensures that the circuit can safely handle the demand for high radiant heat.

**3. Air fryers**
Air fryers, popular for their ability to crisp foods quickly—like rejuvenating leftover fries—rely on powerful heating coils and circulating fans that together draw significant energy. Larger models can reach power levels of around 2,000 watts, which greatly exceeds the safe tolerance for typical household extension cords or even for most power strips. To maintain both food safety and electrical integrity, it’s best to place the air fryer on a kitchen countertop and plug it directly into a wall outlet only during active use. Relocating it from storage when needed may be slightly less convenient, but it drastically reduces the risk of electrical overheating.

**4. Microwaves**
Like air fryers, microwaves are classified as heavy-duty kitchen appliances. Because they rely on magnetron tubes to produce microwaves that heat food rapidly, they require quick bursts of high electrical current. Compact microwaves—often found in travel lodgings or small apartments—operate at approximately 600 to 800 watts, whereas full-sized home or office models typically draw between 800 and 1,000 watts. Although these figures may appear moderate, sustained use or multiple simultaneous devices on the same circuit can push an extension cord past its limits. Therefore, whenever a microwave must be placed on a countertop without its own circuit, it should be plugged into a properly grounded GFCI outlet—one designed to instantly shut off electrical flow if it detects an imbalance.

**5. Air conditioning units (ACs)**
Whether window-mounted, portable, or split-type, air conditioners are among the most power-hungry appliances in the average home. Their motors and compressors consume massive amounts of electricity to cool the air efficiently. Connecting one to an extension cord or power strip can easily result in overheating and potential fire. For example, cooling a standard 150-square-foot bedroom demands a unit rated at roughly 6,500 BTUs, translating to around 1,905 watts of power consumption. Such an energy draw is already near the threshold of what a typical outlet can manage, making an extension cord far too unstable for safe use. Before purchase, homeowners can consult an online BTU calculator to match appropriate capacity with room size, then connect the AC unit directly to a properly rated outlet.

**6. Space heaters**
Electric space heaters, celebrated for their convenience in providing immediate warmth, also represent one of the most frequent causes of household electrical fires. The U.S. Consumer Product Safety Commission (CPSC) attributes approximately 1,700 annual residential fires to portable heaters, a portion of which result directly from improper power connection through an extension cord. Standard models produce around 5,120 BTUs of heat each hour, an output powerful enough to melt or deform a cord’s plug within minutes. Because of this, even brief operation using an inadequate extension cord presents a major fire hazard. Always connect space heaters directly to fixed outlets and avoid sharing circuits with other high-draw devices.

**7. Extension cords themselves**
A surprisingly common mistake involves linking multiple cords end-to-end in an attempt to increase reach. This practice, known as daisy-chaining, is extremely hazardous. Every added connection increases electrical resistance within the overall circuit path, which causes greater heat generation at each junction point. In the worst cases, this heat can accumulate rapidly, compromising insulation integrity and eventually leading the cords to scorch or ignite. Even though an extension cord is not technically an appliance, it plays an integral role in safe power distribution, and coupling them together undermines their designed safety margins.

**In conclusion:**
Under no circumstances should extension cords be used to power any device that draws more than 15 amps or 1,800 watts. Regardless of where these devices are situated—be it kitchen counters, living rooms, or bedrooms—they must be supplied through outlets dedicated to handling such electrical loads. By respecting these limitations, homeowners and renters alike can prevent overloaded circuits, avoid costly equipment failures, and most importantly, protect their homes and loved ones from preventable electrical fires.

Sourse: https://www.zdnet.com/article/dont-plug-common-household-gadgets-into-an-extension-cord/