Summary丨Analysis of 8 major unqualified items of this kind of small heating appliances (business + consumers must see)

Date：2020/12/3　　Clicks：1321

Case question

Electric blankets, electric heating pads, and electric table mats are the most popular small home appliances for heating in winter.

The author often inspects electric blanket products in work practice. In this issue, what are the common unqualified items in random inspection of electric blanket products? And how do consumers "avoid pits" when shopping?

(The picture comes from the Internet)

Note: The following pictures are all real shots

case study

The analysis summarizes the common unqualified items as follows:

01 Unqualified protection for touching live parts


At the opening of the electric blanket connector, the IEC 61032 No. 13 test probe can enter the inside to touch the internal live parts, which does not meet the GB 4706.1-2005 and GB 4706.8-2008 standard 8.1.2 "The test probe should not touch the live parts Components".

This structure may cause electric shock in extreme cases. Good design will prevent the No. 13 test probe (also called test pin) in IEC 61032 from entering the hole and touching the live parts.

02 Unqualified electrical strength at working temperature

The fixing screw of the electric blanket controller shell is close to the copper wire on the circuit board, and 3000V electric strength test breakdown is applied between the live parts and the touched parts (screws), which does not comply with GB 4706.1-2005 and GB 4706.8-2008 Standard clause 13.3 "Electrical strength should not be broken down" requirements.

In layman's terms, the insulation between the live parts inside the product and the surface that can be touched by human hands is not good enough, and leakage may occur in extreme cases.

03 Unqualified moisture resistance

The outer skin of the inner wire where the electric blanket is connected to the body of the blanket is damaged, and the internal electrical connection is not filled with glue or filled to expose the dotted parts. After immersing the flexible part of the electric blanket in water containing about 1% NaCl for 1 hour, the live parts and The 3000V electrical strength breakdown applied between the immersed flexible parts does not meet the requirements of Chapter 15 of the GB 4706.1-2005 and GB 4706.8-2008 standards.

In other words, the product may leak in extreme conditions such as moisture.

04 Unqualified for abnormal work
During the heating test after folding the electric blanket, the measured temperature rise of the heating element surface was 151.2K (limit value: ≤145K). The surface of the blanket body was melted and coked, which did not meet the standard clause 19.106 of GB 4706.1-2005 and GB 4706.8-2008. Requirements.

Electric blanket products are prone to wrinkles during use. In the case of wrinkles, the heating element will generate more heat. If the temperature rises too high, the insulating layer on the heating element is easily damaged or aged faster, which may easily lead to electric shock or fire hazard.

05 Unqualified mechanical strength

The heating wire and internal wire in the electric blanket have not reached the bending times during the 25000 cycle bending test, and the internal heating wire has broken, which does not meet the standard GB 47-6.1-2005 and GB 4706.8-2008 Clause 21.111.1 "Sample" Not to be damaged" requirements.

In this case, the heating wire breaks and cannot generate heat, and the conductor may pierce the insulation and cause an electric shock accident.

06 Failed structural items

The under-bunk electric blanket has a wrinkle resistance <1.2, and it is prone to wrinkles during use. There are no anti-wrinkle measures on the product (such as cloth loops for straps), and it does not meet GB 4706.1-2005 and GB 4706.8-2008 standard 22.107 The clause "should have anti-wrinkle measures" requirements.

For under-bunk electric blankets with wrinkle resistance <1.2, necessary anti-wrinkle measures should be provided to ensure that the electric blanket will not crease. Wrinkles in the electric blanket are prone to local overheating, which can lead to fire hazards. Wrinkles can also easily cause excessive bending and damage to the heating elements of the electric blanket.

07 Power cord and external cord are unqualified

The power cord clamping device of some electric blankets uses cable ties, knots, unfixed molded sheaths, etc. After the electric blanket is subjected to a tensile test of 100N, the longitudinal displacement of the cord exceeds 2mm or there is obvious tension at the terminal. It meets the requirements of "The longitudinal displacement of the cord shall not exceed 2mm" in Clause 25.15 of the GB 4706.1-2005 and GB 4706.8-2008 standards.

The power cord used by an electric blanket is only nominally PVC, without model specifications, and does not meet the requirements of the GB 5023 series of standards, and does not meet the requirements of Article 25.8 of the GB 4706.1-2005 and GB 4706.8-2008 standards.

08 Common failures in electrical clearance, creepage distance and solid insulation

The electrical gap between L\N poles on the circuit board of an electric blanket controller is required to be less than 2.0mm. The standard requirement: ≥2.0 mm, which does not meet the requirements of clause 29.1 of the GB 4706.1-2005 and GB 4706.8-2008 standards.
The electric blanket controller knob can be disassembled after the 22.11 test. The IEC61032 type B test probe touches the metal part of the potentiometer, and the electric gap and creepage distance between the easily touchable metal part and the live part do not meet the requirements of reinforced insulation. GB 4706.1-2005 and GB 4706.8-2008 standards require chapter 29.

Electric blanket products are in direct contact with people and may be used for a long time. Its safety performance is closely related to the safety of people's lives and properties. Electric blanket products originally belonged to the catalog of production licenses. With the further deepening reform of "decentralization, management and service", the management of the production license system has been transferred to the management of the CCC compulsory certification system. Electric blanket products can only be sold when they have obtained the compulsory certification certificate and affixed the CCC mark.

The author recommends that consumers do not choose electric blanket products with too low price when purchasing, look for products with CCC mark, and prefer to buy reputable products of big brands. If you find that there is no trademark or specification parameters (such as RVV) on the plug power cord 300/300 2×0.5mm2), CCC mark, under-berth type electric blanket without wrinkle-proof "cloth loops" at the four corners, etc. are most likely to be counterfeit CCC certified electric blankets.