Power supply UL certification

If I need UL certification for my power supply, does the flyback transformer need to by UL listed?
How much would UL certification cost generally?

Hi,


> If I need UL certification for my power supply, does the flyback transformer need to by UL listed?
The norm to be applied is the IEC 60950.

UL tests in the USA might differ a little from UL tests in Europe.

If you ask UL to quallify your PS, they will apply the UL 60950 norm which is very similar to IEC 60950.

The UL 60950 qualification process is a 3-step job:

1) Preliminary investigation

- The UL safety engineer take a look at your design
- The UL safety engineer tells you which tests your PS must pass
- The UL safety engineer usually finds in 5 minutes the problems that your design might have and will tell you how to correct your design
- He will tell you how the transformer has to be built, the primary-to-secondary distances, the insulation class.


2) EMC and LVD tests

3) UL listing
- you have to declare the manufacturer of your PS
- UL will visit yearly your manufacturer to see if he builds your PS accordingly to the Bill of Material that you gave to UL
- Each visit has a cost of 1000 USD


> How much would UL certification cost generally?
It's gonna cost roughly 10.000 USD.


Enrico Migliore

Enrico,

Thanks.
Are there any alternatives to UL (cost wise)?

Hi,

> Are there any alternatives to UL (cost wise)?


VDE is even more expansive.

UL tests can be done in Taiwan or China.

Enrico Migliore