IEC/UL/CSA 62368-1 Electrical Distance Testing

IEC/UL/CSA 62368-1 has been implemented in most countries and regions as a common standard applicable to IT and communication equipment, as well as computer peripheral products. Compliance of products with the requirements of the 62368-1 standard has become a crucial step to enter the international market. Among these requirements, electrical distance plays a very key role in safety regulation assessment. Prevention of electric shock hazards is the focus of safety regulation assessment, and electrical distance is an important method to meet the requirements for electric shock prevention. UK has compiled and collected relevant materials to provide a brief summary and interpretation of the electrical distance requirements in 62368-1.

 Electrical distance is divided into two categories, namely clearance and creepage distance.

Clearance Requirements of 62368-1

The corresponding clause for clearance requirements in 62368-1 is Clause 5.4.2, which is the primary method for assessing clearance. In addition, Appendix X provides a second alternative method, which is mutually exclusive with the original method.

a) Clause 5.4.2 of 62368-1 requires the assessment of clearance using two paths, namely the Working Voltage Look-up Table Method (Clause [5.4.2.2](5.4.2.2)) and the Withstand Voltage Look-up Table Method (Clause [5.4.2.3](5.4.2.3)), and the higher value of the two shall be adopted. This clause contains extensive content, which is summarized as follows for ease of understanding and application.

Working Voltage Look-up Table Method (Clause [5.4.2.2](5.4.2.2))

Path 1 - Working Voltage Look-up Table Method (Clause [5.4.2.2](5.4.2.2))

Step 1: Determine the Peak Working Voltage (the highest value among the following three voltages):

①　Peak working voltage

②　Peak repetitive voltage, if applicable

③　Temporary Overvoltage (2000V when input voltage does not exceed 250V, 2500V when input voltage ranges from 250V to 600V)

Step 2: Look up Table 10 (for frequencies ≤30kHz) and Table 11 (for frequencies >30kHz) to determine the requiRED clearance.

Withstand Voltage Look-up Table Method (Clause [5.4.2.3](5.4.2.3))

Step 1: Confirm the Transient Voltage based on the actual use of the product:

①　AC mains input, in accordance with Table 12 (values of transient voltage caused by AC mains input)

②　DC mains input

③　External circuits (mainly communication networks), in accordance with Table 13 (values of transient voltage caused by external communication circuits)

④　Measurement, as an alternative to the above three methods

⑤　Step 2: Determine the Required Withstand Voltage:

⑥　The required withstand voltage is equal to the transient voltage, except for circuits isolated from the mains and battery-powered circuits

Step 3: Look up Table 14 (specific look-up values for clearance) to determine the required clearance.

Note: Path 2 can also adopt an alternative method - the Electric Strength Test (also known as withstand voltage test) specified in Clause [5.4.2.4](5.4.2.4), to confirm the sufficiency of clearance based on Table 15 (corresponding values for withstand voltage test). When the withstand voltage test is used instead of Path 2, the distance specified in Path 1 must be satisfied.

General Requirements

①　Both Path 1 and Path 2 must be satisfied, and the higher value of the clearance required by the two methods shall be adopted

②　Consider the altitude correction factor (Clause [5.4.2.5](5.4.2.5)) in accordance with Table 16 (altitude correction factor table)

Clearance Requirements of 62368-1

Creepage Distance Requirements of 62368-1

Compared with the clearance requirements of 62368-1, the creepage distance requirements specified in Clause 5.4.3 of 62368-1 are relatively simple. The summary is as follows:

①　For basic and supplementary insulation, look up Table 17 (corresponding to Table 18 in the second edition).

②　When applying Table 17 and Table 18, the value for reinforced insulation is twice the value for basic insulation.

③　If the circuit frequency is 30kHz < F ≤ 400kHz, the minimum creepage distance shall be referred to Table 18 (corresponding to Table 19 in the second edition). If the value is lower than that in Table 17, the value in Table 17 shall be applied.

④　When the creepage distance is smaller than the clearance, the creepage distance shall be equal to the clearance value.

Products Covered by 62368-1 Certification

The new standard has a wide scope, covering various consumer and enterprise-level products, including:

Information Technology Products:

Computing products, network equipment and peripheral devices: switches, servers, routers, scanners, personal computers, laptops, tablets and terminal equipment.

Communication Technology Products:

Mobile phones, smartphones, telephones, network infrastructure equipment and IP enclosures.

Consumer Electronics Products:

Wearable products, home theater systems, televisions, monitors, cameras, music players, game consoles, musical instruments and virtual reality (VR) products.

Professional Audio Products:

Active speakers, mixers, power amplifiers and signal processors.

Office Equipment:

Copiers, paper shredders, projectors and printers.

Components:

Internal and external power supplies, graphics cards, network cards, motherboards, lasers, batteries and optical disc drives.

iec 62368 Certification Test Items

1. General requirements

2. Injury caused by electricity

3. Fire caused by electricity

4. Injury caused by harmful substances

5. Damage caused by machinery

6. Injury from thermal burns

7. Normal working condition test, abnormal working condition test and single fault condition test

8. Test conditions for equipment containing audio amplifiers

9. Equipment signs, instructions and indicative safety protection

10. Components

11. Overvoltage category

12. Disconnect device

13. Equipment with battery pack and its protection circuit

14. Measurement of creepage distance and electrical clearance

15. Safety protection to prevent the entry of conductive objects

16. Interconnected circuits scheduled to be wired to the building

17. Heat and flame resistance test

18. Mechanical strength test

19. Confirmation of accessible parts

62368 Certification and Testing Institutions

For 62368 certification and testing, qualified third-party testing institutions shall be selected. The specific handling process is as follows:

1. Project Application: Submit an application to a third-party testing institution.

2. Document Preparation: The enterprise prepares relevant certification documents in accordance with the standard requirements.

3. Product Testing: The enterprise sends the samples to be tested to the laboratory for testing.

4. Report Compilation: The certification engineer compiles a report based on the qualified test data.

5. Submission for Review: The engineer reviews the complete report.

6. Certificate Issuance: The certificate will be officially issued after the report is verified.