Keep these 4 points in mind when you apply for the safety certification of the switching power supply.
What is the safety certification?
1.Definition
In order to ensure personal safety, property, environment, etc.and avoid to harm and loss, then make the regulations.
2. Requipment of safety certification:
a. Electric shock b. Fire c. Electromagnetic radiation d. Environmental pollution e. Chemical radiation f. Energy shock g. Chemical corrosion h. Mechanical damage and thermal damage
3. The world's major safety systems
a. IEC system-represented by the European Union b.UL system-represented by the United States
Although these 2 systems are independent of each other, now there is a tendency to recognize each other and move towards consistency.
4. Common safety certification
a. UL-United States b. TUV,VDE,GS-Germany c. CCC-China d. PSE-Japan e. CE-EU f. KC KCC MEPS-Korea g. SAA RCM C-TICK-Australia, h. PSB-Singapore

Application process for safety certification
1. Submit application materials to the safety regulatory agency.
2. The safety certification body will give a reply on whether to accept the application within the promised time.
3. After the safety agency accepts the application, the applicant begins to send samples for safety testing.
4. If the sample passes the safety test, the safety certification agency arranges factory inspection (UL called IPI), if it fails the test, it will be returned to the applicant, the applicant make improvements to the items that have not passed the test, and then re-send the sample for testing. If the second time fails, you need to reapply.
5. After the factory inspection is passed, the safety certification body will issue a certification certificate or a letter of authorization for the use of safety signs, and the applicant can use the certified logo on the product. If the factory inspection fails, the certification body will give the applicant a period of re-apply.
6 In the future, the certificated product will be transfered and inspected. UL is generally four times a year, CCC is once a year. The period of other certification agencies is mostly once a year. Follow-up inspections mainly check the consistency of products, but quality systems such as CCC and TUV are also reviewed.
Basic safety requirements for electronic product:
1. Withstand voltage (electric strength)-prevent electric shock damage
2. Insulation resistance-prevent electric shock injury
3. Grounding resistance-prevent electric shock injury
4. Leakage current-prevent electric shock damage
5. Electromagnetic compatibility-anti-electromagnetic interference ability and impact on other electronic products
6. Fire resistance-prevent fire hazard
7. Mechanical structure-prevent damage, burns, etc. caused by mechanical structural defects.
8. Energy shock-prevent fire or arc burns caused by high current
Safety requirements for electronic products in the manufacturing process
1. Withstand voltage: the main consideration is the withstand ability of the insulation system of the product under abnormal high voltage. The working voltage is less than 50V, and the withstand voltage test is generally not performed.
2. Insulation resistance: the main consideration is the insulation performance of the product
3. Leakage current: The main consideration is that the product is caused by distributed capacitance or insulation characteristics under the maximum operating voltage and maximum operating current.The leakage current of the earth or the contactable interface is related to the insulation of the product.
4. Grounding resistance: The main consideration is the insulation breakdown of the product, or the leakage of the charge under normal working conditions, and the energy that can quickly introduce these charges into the ground.
Force, this is a protective measure, which is not considered in products that are not grounded.
5 safety distance
6 electromagnetic compatibility
7 Fire resistant and flame retardant
8 Mechanical structure damage and thermal damage
Common safety parts for electronic products
a. Fuse
b. Wire
c. X capacitance and Y capacitance
d. High voltage capacitor
e. Transformer, inductor
f. Varistor
g. Plastic parts
h. Insulation spacer
i. PCB board
j. Model label or nameplate
k. Warning signs
l. Optocoupler
m. Shell
n. cooling fan
Safety parts are one of the key control parts of safety certification agencies. Any safety certification agencies will issue a list of safety critical parts for certified products, and the safety certification agencies will conduct consistency checks based on this list. If the specification model and manufacturer are indicated in the list, which should be also used on the certification. If the manufacturer is not indicated but the specification model is indicated, it may also be specified that the corresponding certification is required, and the specified manufacturer must be used. The key control parts can be changed only after the testing passed.