W D Stewart wrote:
>
> I'm looking for design information on the width and thickness of
> traces for a printed circuit board I am trying to design.  It will be
> carrying 220VAC at 8, 5, 2, and 1 amps and 120VAC at 4 and 1 amps.  Is
> there any general reference guide that gives 'rule-of-thumb'
> guidelines re this?
>

The conductor's cross-sectional area requirements can be obtained from
IPC-D-275, Table 3-4, or IPC-2221, Table 6-4.  Or better yet, visit the
website of UltraCAD Design Inc, <http:\\ultracad.com>, Doug Brooks has
done an excellent job in developing and making available a model for
calculating the conductor cross-sectional area requirements for limiting
the thermal rise above ambient.  These models will replicate the above
referenced IPC charts and have been extended (by some addition
referenced technical papers) or get ahold of the latest copy of Printed
Circuits Design magazine, his technical paper and model is in his
column.

The other concern you've got is voltage, simply stated, you can use the
IPC design conductor spacing tables ---- but I suspect for the above
application they may not be suitable.  This is because the voltage 220 &
120 Vac are electrical "primary power", and are subject to regulatory
requirements (UL, CSA, VDE, IEC, etc) and they have different conductor
spacing requirements for "exposed" conductor spacing.  In the USA, 220
and 120 Vac are the same voltage with respect to neutral and ground (120
Vac).  As I recall, for USA the requirement was 1.5 kV + twice the
applied voltage (1.5 + 2 * 120) or 1750 Vac test voltage and spacing.
If you want/need, I can dig in my files and come up with the spec.
requirements.  I seem to recall the Eurpoean requirements were like
about 2.5 kV.

Hope this helps, if you need more info. (if other technetters don't
respond with addition a info.) drop me an e-mail


Ralph Hersey

Ralph Hersey & Associates
3885 Mills Way
Livermore, CA 94550-3319
PHN/FAX: 925.454.9805
e-mail: [log in to unmask]

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