Many Duwi brand extension cords are sold in Auchan and Leroy Merlin stores.
I bought and tested five models.
The Duwi brand belongs to the Russian company Pan Electric. Surely you have come across their second brand REV, under which cheap LED bulbs are produced, which are sold in the same Auchan.
The first three extension cords bought in Auchan have a similar design and are designed for loads up to 2200 W. The remaining two extension cords purchased from Leroy Merlin are rated for loads up to 3680 watts.
All extension cords have grounded plugs and sockets (some with protective shutters, some without), the plug of the first four extension cords has a convenient handle. Includes quick-release wall mount.
Let's start with the first three extension cords rated for up to 2200 watts.
Extension cord 3 sockets, 5 meters (214 rubles).
Extension cord 4 sockets, 3 meters with a switch (335 rubles).
Surge protector 5 outlets, 5 meters (555 rubles).
To test the operation at maximum load, a current of 10 A was passed through the extension cords.
After 10 minutes, the extension cords became very hot. The temperature of the coiled extension has reached 95 °.
At one point, the temperature exceeded 102 °. There is a smell of overheated plastic.
The temperature of the separately lying cable was 55 °.
No significant heating of the plug and socket strip was detected.
Extension cords are difficult to handle the specified maximum load when the cable is fully extended. At the same time, the cable is working at the limit of its capabilities. In an amicable way, you should not use these extension cords with a load current of more than 6A (power 1380 W).
On the extension cables there are inscriptions "3G 0.75mm²", a copper cable with such a cross-section at a current of 10A would not get so hot. We'll have to cut and measure!
The wires consist of 22-23 wires, each of which has a diameter of 0.18-0.19 mm (total cross-section 0.56-0.65 mm²).
The resistance of the conductors in a section of 4 m 53 cm of the wire was:
Brown wire: 275 mΩ (60.7 Ω / km). This resistance corresponds to a copper conductor cross-section of 0.29 mm².
Blue wire: 302 mΩ (66.7 Ω / km). This resistance corresponds to a copper conductor cross-section of 0.26 mm².
Yellow-green wire: 243 mΩ (53.6 Ω / km). This resistance corresponds to a copper conductor cross-section of 0.32 mm².
The discrepancy between the measured and calculated cross sections indicates that the wire cores are not made of copper. This is confirmed by heating - the color of the cores changes from copper to gray.
The socket block housings are fastened with screws with a non-standard triangular head. The wire is fixed in the socket strip with a bar with two self-tapping screws. There is no clutch to protect the wire from kinking.
The body of the socket strip burns well.
Contact strips are made of 0.4 mm thick metal. The base metal of the strips is steel (the metal is magnetised).
The wires are soldered to the strips, the quality of the soldering is high.
After reconnecting the plug, one of the grounding pins is crumpled.
On extension cords with a switch, the push button breaks only one wire and has a built-in blue indicator. The LED is not centered.
The design of the strip of sockets of the extension cord with a button.
Some of the wires are soldered, some are welded.
The third extension cord is called a surge protector. It contains a board with a 14D471K varistor (470 V) and a 0.1 μF 275 V capacitor.
The soldering quality of this model is much worse than that of the previous two.
However, it can be a "lottery" - some copies are welded and welded well, and some like this.
The 2200 W extension cords and filter use a wire with conductors from an unknown alloy (however, no one promised copper);
The physical cross-section of the conductors is about 0.6 mm², according to the properties of the wire, they correspond to copper ones with a cross-section of about 0.3 mm²;
The socket block housings are made of flammable plastic;
Contact strips are made of steel;
Extension cords and filter can barely handle 10A (2200W) loads. The wires overheat, especially if they are not straightened;
The switch button breaks only one wire;
The blue indicator LED is off-center, which looks sloppy;
The surge protector contains only a varistor and a capacitor. There is no thermal fuse;
The quality of soldering varies from piece to piece.
I am not suggesting that such extension cords are dangerous and should not be used. For a small load (up to 6A, up to 1380 W) it is quite possible, but it is better under supervision and not to leave such extension cords permanently connected to the network. The two extension cords rated for 3680 watts turned out to be much better. Looking ahead, I will say that they have copper conductors with an honest cross-section and they can withstand the stated load without any problems. I'll tell you about them in the near future.
© 2021, Alexey Nadyozhin
For ten years I have been writing every day about technology, discounts, places of interest and events. Read my blog on the site ammo1.ru, in LJ, Zen, Mirtesen, Telegram.
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