UL Certification question

[Julew]

Hello,

I don´t know too much about UL certification. We have a PCB and we sell it in a plastic enclosure without power supply and in a metal enclosure with power supply. Both plastic and metal+power supply are UL294 listed. If we certificate our PCB, the combination of both pcb+enclosure is UL294??? Thanks!

Julen

 

[edaenrico]

Hi,

take a look at this thread: Started by hithesh123‎, 06-09-11 13:18


>I don´t know too much about UL certification. We have a PCB and we sell it in a plastic enclosure without power supply and in a metal
> enclosure with power supply. Both plastic and metal+power supply are UL294 listed. If we certificate our PCB, the combination of both
> pcb+enclosure is UL294??? Thanks!

I don't understand much. Please be a bit clearer.

A power supply can be UL qualified in 2 ways: Open Frame, Plastic case, or Metallic case.

Plastic case
------------
- The plastic must have a Yellow Card issued by UL
- The PS will be Class 2
- The case can be left floating (not connected to earth)
- You can also qualify the plastic case as a FIRE ENCLOSURE CASE. That means that you have to spend a bit more in the plastic material.


Metallic case
-------------
- The PS will be Class 1
- The case MUST be connected to Earth


Enrico Migliore

 

[Julew]

Hello,

Sorry for my vague description.

The question is:

If A is UL listed and B is UL listed, is A+B UL?

We have to pass UL294 and in this standard they always talk a system, not about a product. Thanks!

 

[edaenrico]

Hi,

> If A is UL listed and B is UL listed, is A+B UL?

You should ask to a UL safety engineer.

I would say that A+B is not "UL listed" for sure because the UL file number is issued after a test process.

Enrico Migliore