Before the cold sets in, check your extension cords: three common spots where they should never be placed at all

Before the heating season begins, it’s useful to walk through the apartment not looking for “dangerous wiring,” but rather imagining several familiar scenes: a cable disappearing under a carpet, running through a door frame, being squeezed by furniture, or lying there for so long that no one has checked it in years. Russia’s Emergency Situations Ministry reminds people of three key points in its 2026 guidelines: extension cords are meant for temporary use and should not be run under carpets or through door frames, and cords with damaged or cracked insulation must not be used.

Therefore, the main question in autumn is not “Does the extension cord work?” It’s important where it is placed, its condition, and what power level is intended to be passed through it.

Hiding an extension cord under the carpet seems like an almost perfect solution: no one trips over it, the room looks neater, and the outlet is finally where it’s needed. But it is precisely this kind of covering that emergency services do not recommend.

Two problems arise here at once.

• First, the wire ends up in a place where it can be constantly pressed by feet and furniture. Damage to the insulation develops unnoticed precisely because the cable is hidden.

This doesn’t mean that any cable under a rug will definitely overheat. But the combination of “invisible wire + mechanical stress + high-power device” is clearly worse than a properly installed, functional cord. Especially before connecting a heater. If the wire is hidden under a rug and you can’t check its condition throughout its length at a glance, autumn is a good time to pull it out and find another solution.

Another classic setup: there’s a power outlet in one room, but the device needs power in another, so an extension cord is run under the door. As long as the door is open, it seems harmless. But then it gets closed at some point.

The cable gets compressed by the door frame or threshold, people walk on it, and it’s bent in the same spot over and over. This is exactly why emergency services specifically warn against running extension cords under door thresholds and openings—the wires can get rubbed against and damaged.

The danger here isn’t some single dramatic moment. A slow, mechanical damage is much more likely. From the outside, the cable still appears almost normal, but at the point of constant bending, the insulation has already become stiff, crushed, or cracked. That’s why inspections before cold weather should start right where the wire touches the door, furniture legs, or sharp edges.

If there are cracks in the insulation, severe bends, crushed areas, or the inner layers of the cable are visible, such an extension cord shouldn’t be “kept just for the lamp.” Emergency services explicitly classify products with damaged insulation as those that should not be used.

This is the most interesting scenario because nothing wrong seems to be happening on the surface. Five years ago, it was necessary to connect a TV and a lamp. A dolly was placed behind the cabinet. The furniture was moved back. Everything works fine. This is exactly how a temporary wiring setup gradually becomes permanent wiring without anyone noticing.

The Emergency Situations Ministry reminds that household extension cords are intended for temporary connection of appliances and should not be used as a permanent wiring solution. Another issue arises with furniture: no one can see the plug, outlet, or cable itself, allowing dust to accumulate there. The cord may also get compressed by a cabinet leg. The contacts can weaken or start overheating, and these problems are only noticed after the furniture is moved. Therefore, before the heating season begins, it’s advisable to move any nearby furniture at least once to check such overlooked areas.

The Emergency Situations Ministry lists discoloration of plastic, melting, sparking, and a burning smell as signs that indicate the equipment should be stopped using immediately and a professional should be consulted.

A power extension cord that could easily power a router and a desk lamp has not yet proven suitable for a heater.

Electric heaters are considered high-power household appliances. The Emergency Situations Ministry recommends avoiding the use of extension cords for heaters whenever possible. If one is necessary, the rated power of the extension cord must be at least equal to the power of the connected device.

Therefore, before connecting, you need to find two numbers.

• The first is the power consumption of the heater, indicated on the label or in the instructions.
• The second is the maximum load capacity of the extension cord. This can be specified in watts or in terms of maximum current.

To give an idea of the scale: at a voltage of 230 V, an extension cord labeled 10 A corresponds to approximately 2.3 kW of theoretical power, while 16 A corresponds to approximately 3.7 kW. This is calculated using the simple formula P = U × I, and it is not a recommendation to overload the wires. You should follow the specifications of the specific product, the device’s instructions, and adhere to the lower of the two specified limits.

If it’s completely impossible to find the specifications for an old power strip, relying on the idea that “it worked before” to connect a powerful heater is a poor approach.

A very common autumn setup looks like this:

• A TV, chargers, and a lamp are connected to one power strip;
• A free socket appears nearby;
• A heater is connected to that socket as well.

However, an extension cord doesn’t have a separate power limit for each outlet. The restriction applies to the entire load at once.

The Emergency Situations Ministry warns that the total power consumption of connected devices may exceed the allowable load, leading to overheating of wiring and connections, as well as damage to insulation and outlets. Let’s take a simple example. A heater consumes 2000 watts. An electric kettle uses about another 2000 watts. If both are accidentally connected through the same extension cord and operate simultaneously, the total power consumption becomes around 4000 watts. For an extension cord rated at 3500 watts, this already exceeds the nominal load, even though each device individually seems completely normal.

That’s why the phrase “there are two more free outlets” tells us nothing about how much power remains.

After the heater has been running for ten minutes, it is useful to pay attention not only to the room temperature. The outlet, plug, and connections should show no obvious signs of overheating. Smells of hot or melting plastic, noticeable darkening, sparking, or deformation of the housing are not reasons to wait until tomorrow to check it. The Emergency Situations Ministry recommends stopping use of the equipment if such signs appear and calling a qualified electrician.

The same applies to an outlet that holds a plug loosely for too long. Even an automatic circuit breaker is not an excuse for poor contact. The Emergency Situations Ministry specifically notes that protective devices do not prevent fires caused by weak connections: localized heating can occur right at the problematic connection point.

You don’t necessarily need to inspect the entire electrical system. Start with the extension cords that are actually in use.

• Pull the wire out from under the carpet.
• Check the areas near doors and thresholds.
• Make sure the cable isn’t compressed by furniture.
• Inspect the plug, body, and insulation along its entire length.
• Then find the maximum load rating and consider what devices are connected at the same time.

Pay special attention to the location where you plan to place the heater. The safest approach here is not to simply find the thickest extension cord in the house, but first to check the device’s instructions and see if it can be connected directly to a suitable fixed outlet. The emergency services recommend avoiding extension cords whenever possible.

And if the only way to place the heater in the desired spot requires running the cord under a carpet, pressing it against a door, and leaving it there until spring, then the issue is no longer about choosing a more attractive cable. This is a temporary solution that is being used as if it were permanent wiring.

Before the cold sets in, it’s useful to locate such spots before you need a heater at all. The extension cord shouldn’t draw attention every day. But precisely for this reason, it’s worth remembering at least once a season where it is placed, what is connected to it, and whether the inconspicuous cord behind the sofa has become a permanent part of the apartment.