The extension cord is the same necessary element of electrical wiring in the house, like sockets, switches and other equipment.

In the store you can find dozens of varieties. Which one to choose and which parameters to pay attention in the first place.

Wire length and number of sockets

Remember that the longer the carrying, the greater the voltage loss will be. For household appliances, the optimal extension cord length is from 3m to 7m.

In this case, you can connect the load in them with a capacity of no more than 3.5 kW (up to 16A) at the same time. It depends on the cross section of the wire.

For more, the contacts of the sockets are simply not calculated, no matter how thick the wire is.

By the way, many sockets for sockets are needed not to simultaneously connect a large number of devices, but in order not to constantly pull out the plug, thereby protecting it from loosening the contacts.

Wire section and mark

The cross-section of the wires to connect the load room equipment (TV, computers, refrigerators), choose at least 0.75 mm2.

The type of wire is most often PVA with PVC insulation.

At the same time, the diameter of the wire itself (not a separate wire) is desirable to have from 5mm and above. If this is not the case, the manufacturer is likely to save on something, either on copper or on insulation.

Another can be used brand KG, instead of PVA. It is more resistant to negative temperatures and changes in weather conditions. For outdoor or garage use, this choice will be more appropriate.

PVA drag several times on the concrete floor, and its insulation will come to an end. KG is more resistant to such operating conditions

Here are the suitable wire sections for high-quality carriers, and that they can be safely turned on without the risk of overheating (refrigerators, washing machines, TVs, drills, grinders, heaters, etc.):

Mechanical protection

A quality model must have protection against stretching and bending the wire.

This applies equally to the plug and the point where the conductors are inserted into the extension casing.

Never carry around with twisted wires. First, it will sooner or later lead to damage to the cores, and secondly, such a cable will simply heat up.


Before you buy an extension cord, look at what kind of plug it has:

It must be have a cast which is detachable

If the plug is not molded, and it can be disassembled, then there is a risk of running into a dubious product. It is the easiest way to make such forks in an artisan way.

For the production of solid, at least you need some professional equipment.

In addition, if your equipment with a plug without a Euro connector, then an extension cord with an euro socket is contraindicated. The use in this case of euro adapters and adapters greatly increases the transient resistance.

It also breaks the grounding system, which can lead to electric shock. Some devices and tools to connect without grounding elementary dangerous.

The contact resistance of one contact in the new model should be no more than 0.05 Ohm. During operation, it may deteriorate to 0.1 Ohm.

That is, at a nominal load of 10A, only on one of the contacts “plug-socket” you can lose up to 10W in power every hour.