Regulation Aspect

Q1

Why the input voltage marked on the spec. sheet is 88~264 VAC while the label on the power supply says that it is 100~240VAC?

Ans

During safety verification process, the agency will use a stricter standard -- ?0%(IEC60950 uses +6%, -10%) of the input voltage range labeled on the power supply to conduct the test. So, operating at the wider input voltage range as specified on the spec. sheet should be fine. The narrower range of input voltage labeled on the power supply is to fulfill the test standard of safety regulation and make sure that users insert input voltage correctly.

Q2

Will MEAN WELL's products with CE marking meet the EMC requirements after assembling into my system?

Ans

We cannot guarantee 100% that the final system can still meet the EMC requirements. The location, wiring and grounding of the switching power supply in the system may influence its EMC characteristics. In different environment or applications, the same switching power supply may have different outcomes. Our test results are based on setup shown in the EMC report.

Q3

What is different between information (EN60950-1) and medical (EN60601-1) safety standard?

Ans

According to safety standard, the leakage current in EN60950-1 Class I cannot exceed 3.5mA; in EN60601-1 cannot exceed 0.3mA. Others criteria like safe distance and numbers of fuse are also different. Please consult the diagram below:

Q4

What is class 2, class II and LPS? What is the difference between class I and class II?

Ans

Class I: Equipment where protection against electric shock is achieved by using basic insulation and also providing a means of connecting to the protective earth conductor in the building where by routing those conductive parts that are otherwise capable of assuming hazardous voltages to earth ground if the basic insulation fails. This means a class I SPS will provide a terminal/pin for earth ground connection.
Class II: Equipment in which protection against electric shock does not rely on basic insulation only, but in which additional safety precautions, such as double insulation or reinforced insulation are provided, there being no reliance on either protective earth or installation conditions. This means a class II SPS does NOT have a terminal/pin for earth ground connection.
LPS: When an electronic circuit is powered by a limit power source (LPS), its output current and power are under the limitation shown in IEC60950-1 Table 2B, and the risk of fire can be reduced significantly. So, the safety distances and flammability rating of components can be much lower. Therefore, the plastic enclosure of these power supplies could use HB flammability rating to reduce cost. This definition comes from ITE product (IEC/EN/UL60950-1).

Class 2: When an electronic circuit is powered by class 2, its output current and power are under the limitation shown in UL1310 Table 30.1, and the risk of fire can be reduced significantly. So, the safety distances and flammability rating of components can be much lower. Therefore, the plastic enclosure of these power supplies could use HB flammability rating to reduce cost. This definition comes from UL class 2 power unit (UL1310).

Q5

What is SELV for information products?

Ans

This regulation applies to the secondary circuitry. The circuit should be designed to guarantee that under normal operating conditions, the voltage between any two touchable points should be less than 42.4Vpeak or 60Vdc. For class I equipment, it refers to "between any touchable point and the ground." Under single fault conditions, the voltages between any two conductors of the SELV circuit and between any one such conductor and earth shall not exceed 42.4V peak or 60Vdc for a period longer than 0.2 seconds. Moreover, a limit of 71V peak or 120Vdc shall not be exceeded. According to requirements below, MW SPSs can comply with SELV. IEC 60950-1 (ITE SPS): voltage of o/p circuit is less than 60Vdc under normal condition. IEC 61347-2-13 (LED SPS): voltage of o/p circuit is less than 120Vdc under normal condition.

Q6

What is LPS ? If the power supplies can meet LPS, what is the benefit for the end product?

Ans

The requirement of LPS is from IEC60950. It means the product output shall not exceed 60V/8A/100W under the normal and abnormal condition.
If the power supplies can meet LPS , the end product does not need the fire enclosure.

Q7

What is LVLE ? If the power supplies can meet LVLE, what is the benefit for the end product?

Ans

According from UL8750 definition below:
a. 0-30Vdc output voltage: Maximum 8 amps
b. 30-60Vdc output voltage: 150/V amps
If the power supplies can meet LVLE , the end product does not need the fire enclosure.
 

Q8

What is MOOP and MOPP?

Ans

a. MOOP: provide adequate protection to the operator
b. MOPP: provide adequate protection to the patient
c. MOP: only one protection
MW products declare 2 MOPP means that MW product can provide two adequate protections to the patient.
It minimum the risk and also suitable for the patient.
 

Q9

There is a definition of SELV in IEC61347. Is it the same with IEC60950?

Ans

No, they are different. SELV means the LED driver will use a safety isolating transformer with double or reinforced insulation and the output voltage shall not exceed 120Vdc.
This is good for the end product safety certified if the LED driver with SELV output.

Q10

What is Type HL?

Ans

The requirement of Type HL is from UL8750. It provide one option for evaluation of LED drivers that are intended for use in a Class I, Division 2 hazardous location luminaires.
It is simplify the procedure for the manufacture to apply the explosion-proof luminaires.