Recently, CCTV conducted spot checks on some power strips on the market:

1. Wire diameter detection

The wire diameter refers to the cross-sectional area of a single metal wire inside the conductor of a plug-in version. The larger the wire diameter, the higher the electrical power that can be carried, which is the core indicator of the power strip.

The red circle below represents the metal wire inside the wire:

According to the requirements of the new national standard, the wire diameter must be above 1.0 square millimeter. A wire diameter that is too thin can generate heat during use due to excessive carrying power, causing a sharp rise in temperature and, in severe cases, leading to spontaneous combustion.

Through testing, only 1 out of 15 batches of products purchased from the market meets the requirements. A cheap power strip with a nominal wire diameter of 0.75 square millimeters, but the actual wire diameter detected is only 0.14 square millimeters.

In the experiment, four appliances working simultaneously (up to six devices can be plugged in) were plugged into the unqualified power strip. After being powered on for more than 10 minutes, the cable part began to melt, emitting thick smoke, the insulation skin cracked, and the temperature soared to 200 degrees Celsius. In this situation, if exposed to flammable materials such as curtains and carpets, it is highly likely to cause a fire.

2. Flame retardancy testing of materials

The flame retardancy of materials includes two aspects of testing. One is to use a 650 degree Celsius hot wire as a heat source to contact the panel for 3 seconds, requiring no ignition or automatic extinguishing within 30 seconds after ignition; The new national standard has added a second test, requiring the use of an open flame to touch the panel for 30 seconds, and requiring it to not ignite or automatically turn off within 30 seconds after ignition.

Through testing, only 5 batches of samples can meet the requirements.

Most products can pass the hot wire test, but cannot pass the open flame test.

The two types of detection simulate two different risk scenarios, one is whether electrical faults and overheating have an impact on the power strip; One is whether the malfunction or fire of electrical appliances or other items has an impact on the power strip. Obviously, open flame detection requires higher flame retardancy of the product.

3. Leakage protection detection

The leakage protection detection of the power strip can be divided into two aspects: one is whether the leakage protection device of the power strip itself is effective; The second is whether the design of the power strip effectively avoids accidental electric shock.

The leakage protection device of the power strip itself is mainly the grounding wire. When in contact with a leakage electrical device, the grounding wire can guide the current into the ground to prevent personnel from getting electric shock.

In the inspection, some inexpensive power strips have two plugs themselves and no grounding wire at all; Some are three plug connectors, but the grounding wire only has an outer rubber ring and no metal wire inside. It is just a decoration and has no practical function.

The design of the power strip should avoid several issues:

1. The edge is too narrow, allowing one of the two plugs of the appliance to be inserted into the socket and the other to be exposed, resulting in electrical leakage;

2. The internal live plug sleeve is too close to the panel, and the plug does not need to be fully inserted to make contact, resulting in leakage;

3. Without a protective door with a socket, users, especially children, can easily insert sharp metal objects (such as pins, keys, etc.) into the socket, causing electric shock.

The red circle below is the socket protection door:

There are no qualified samples for this test.

The main problem with cheap products is cutting corners on the grounding wire; Other products are mainly due to the lack of installed socket protection doors.

The new national standard for power strips was released in October 2015 and will be enforced in April 2017. Products that do not meet the requirements of the new national standard will not be allowed to be sold on the market. Before that, consumers still need to identify and choose high-quality products on their own.

(Information source: CCTV13 "Weekly Quality Report")