Richard,

Common occurance especially when the product moves into
the high voltage testing called HIPOT (for HIgh POTential).
This is where the test engineer applies a high voltage
across the primary AC input side of the product to the
secondary output of the power supply and also applies
a high voltage across the primary AC input to chassis
ground.

Typical test setup is

1) Tie HOT and NEUTRAL together on the primary AC input
   so that you don't burn up the power input.

2) Apply 1500VAC (low current) between the primary side
   and ground.  Failure is a spark over or complete
   short.

3) Apply 3000VAC between the primary side and the
   secondary side of the power supply. Failure is again
   a spark over or complete short.

Can be avoided by designing in the requirements with
of course the cooperation of engineering in advance.
That requires participation in a design review prior
to artwork generation and/or engineering signing up
to a design guideline rules for artwork.

I wrote myelf into the ECR/ECO and design review
processes in several companies.

The failing of seperation of traces in the HIPOT test
is a VERY common failure in the test lab.

Regards,  Doug


Hamilton, Richard -4454 wrote:
>
> Hello TechNeters,
>
> I am not sure if this is appropriate for TN, if not I apologize in advance.
>
> We seem to be having continuous delays in processing our product through
> product safety testing (UL). I am wondering if anyone else has experienced
> this and what steps were taken to expedite the process.
>
> This is something that has been going on for years now, and I just thought
> there may be some good resources here on TN.
>
> Please feel free to respond off-line if you prefer.
>
> Thank you all in advance.

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