The inexpensive surge protector Buro 300SL-1-G is sold in many stores and costs from 240 rubles.
I studied it, measured the parameters and checked what metal the cable cores are made of.
The manufacturer claims the length of the cable is 1 meter, in fact, its length from the point of exit from the plug to the point of entry into the socket block is 83 cm. Even if you measure from the center of the socket closest to the wire to the center of the plug, you get 94 cm.
The label indicates a maximum load of 7 A, the maximum power is not indicated.
The rear side of the socket block also lists only the maximum current of 7A.
But on the plastic of the plug there is an inscription “16/250 ~”, because of which the buyer can mistakenly connect a load that consumes 16 amperes to the extension cord.
The inscription on the wire: "H05VV-F 3G 0.75mm²".
The body of the socket block is made of combustible plastic.
When measuring the resistance of power lines, it was found that each time the switch is turned on, the resistance changes from 0.6 to 6 Ohm (each time the switch contacts are slightly in a different position and due to their poor quality, the resistance is different). For reference: a good power switch should have contact resistance less than 0.05 ohm (50 mOhm).
To check the operation of the filter in the maximum load mode, a current of 7 A was passed through it.
After 30 minutes, the temperature of the outer sheath of the cable reached 40°C.
The circuit breaker body temperature has exceeded 71°C.
Significant heating of the plug and contacts of the socket block was not recorded.
Due to a poor-quality switch, the extension cord cannot cope with the declared load.
The brown wire consists of 24 wires, blue and yellow-green of 23.
Each wire has a diameter of 0.185 mm (wire cross section approx. 0.65 mm²).
The resistance of the cores in a segment of 65 cm of the wire was:
Brown wire: 36.8 mΩ (56.6 Ω/km).
Blue wire: 30.1 mΩ (46.3 Ω/km).
Yellow-green wire: 33.5 mΩ (51.5 Ω/km).
This resistance corresponds to the cross section of the copper conductor 0.31-0.38 mm²
Presumably, the cores are made of aluminum coated with a thin layer of copper. Due to the poor quality of workmanship, the resistance of the wires and the number of cores in them are different.
When heated in the flame of a lighter, the color of the cores changes from copper to gray.
The socket block is collapsible, its two halves are fastened with four self-tapping screws with triangular heads. There is an anti-tear bushing.
The wires are soldered to the switch and the ground bar. The wires coming from the switch are welded to the current-carrying strips. Found one long strand of red wire almost touching the ground bar.
The soldering quality is poor.
The only line filter element is a 14D471K varistor (classification voltage 470 V, rms response voltage 300 V, absorbed energy 115 J).
Contact strips have a thickness of 0.4 mm, the metal is magnetized. Grounding strips are riveted to the busbar.
The Buro 300SL-1-G surge protector cable withstands the declared load (7A, 1600 W), but the switch overheats.
The maximum current of 16A is indicated on the plug, which can lead to consumer error and fire, because the body of the socket block is made of combustible plastic. A wire with a cross section of 0.65 mm² was used with strands of an unknown metal (presumably aluminum coated with a thin layer of copper), with a resistance corresponding to copper strands of 0.3-0.4 mm². The contact strips are made of steel. The soldering quality is poor. In the tested instance, an uncut strand of wire was found, which can close to the ground bus.
I filmed the entire testing process on video and edited a short video.
https://www.youtube.com/watch? v=QAF2q55ATFw
Peace for everyone!
© 2022, Alexey Nadezhin
For twelve years I have been writing about technology, discounts, interesting places and events. Read my blog site ammo1.ru, in Learn, Zen, Mirtesen, Telegram.
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#extension#network filter#buro#test