Safety Specification for PCB Design (I)

Safety regulations are product safety requirements in product certification, including the safety requirements of product parts and the safety requirements after the finished product. Safety is actually a product of the Chinese themselves, and foreign countries generally call it regulatory.

What is safety?

Safety Compliance - The best English explanation should be Production Compliance.

It refers to the product's life cycle from design to sale to end users, throughout the life of the product, relative to the laws, regulations and standards of the place of sale. This product safety compliance not only includes product safety in the ordinary sense, but also includes requirements for electromagnetic compatibility and radiation, energy saving and environmental protection, food hygiene, etc. It should be more than just a requirement, a standard, a certificate, a test report can replace or explain, it should be a product safety responsibility and activities throughout the product life cycle.

Simply understanding safety as a certification should be one-sided. Certification is only a means or process for assessing product compliance, but it is not a required means or process. This conformity should be assessed at the beginning of the product design, but not necessarily through third-party testing, to examine the conformity of the product to relevant laws, regulations and standards, to assess the foreseeable or unforeseen risks, to ensure users Avoid as expected or unforeseen personal injury or property damage as much as possible during use.

Safety regulations can simulate electric shock, fire, mechanical injury, thermal injury, chemical injury, radiation injury, food hygiene, etc. that may occur under normal or abnormal use by a series of tests. Such hazards are prevented by the corresponding design before the product leaves the factory.

This safety specification applies to PCB safety design for weak point devices with input voltages below 600V.

Part 1: Basic knowledge of safety regulations

There are fundamental differences between UL and VDE safety standards. UL specifications focus on preventing fire hazards, while VDE specifications are more about operator safety. For power supplies, VDE is the most stringent electrical safety standard.

The following safety parts are required to have a VDE and UL certificate (if the model is also in Canada plus a CUL certificate):

1. Transformer (skeleton, insulating tape, polyester insulation tape)

2. Filter (skeleton, insulating tape, polyester insulation tape)

3. Optocoupler

4. Y capacitor

5. X capacitor

6. PCB material (including the yellow card of the board)

7. Combustible plastic material (including front panel, power board support rubber column, power board insulation PVC, fuse holder, power cord socket VH-3, etc.)

8. Fuse

9. Thermal casing

10. Large capacity electrolytic capacitors.

11. Various types of wire