Also, if you are doing it for UL approval, you need 5mm spacing at 500V.
Regards,
Steve Smith, C.I.D.
Product Engineer
Staco Energy Products Co.
Web Site: www.stacoenergy.com
& www.stacopower.com
> -----Original Message-----
> From: DesignerCouncil [mailto:[log in to unmask]]On
> Behalf Of Gary
> Ferrari
> Sent: Wednesday, January 18, 2006 4:29 PM
> To: [log in to unmask]
> Subject: Re: [DC] Electrical spacing in IPC2221 spec
>
>
> Ron,
>
> You are not quite correct in your assumptions. First, the "A" side of
> the table is for component lead terminations, not lands and
> conductors.
> The lands, as well as conductors, fall on the "B" side of the table.
> That said, the B2 value would be higher than the A6 value since there
> are always traces of contamination on the surface of the board which
> will affect the isolation characteristics. Whereas the component leads
> face air as an insulator and will not see the full effects of surface
> contamination.
>
> Hope this clears it up some.
>
> Regards,
>
> Gary Ferrari
> Ferrari Technical Services
> 860-350-9300
>
> Ron O wrote:
> > Can anyone help interpret the IPC2221 Electrical Conductor
> Spacing chart
> > 6-1 (pg 39)?
> > I have a pcb requirement of 500V spacing between nets. Board is FR4
> > 2layer, soldermask both sides, no conformal coating. Based
> on the chart,
> > I need a B4 spacing (0.8mm) for the soldermasked conductors
> and an A6
> > spacing (1.5mm) for the exposed pad areas (I'm assuming
> this is pad to
> > pad spacing not pad to coated trace spacing).
> >
> > Is my interpretation correct so far?
> >
> > Next question is the column B2, which applies to uncoated (no SM or
> > conformal) and has a spacing requirement of 2.5mm. So this
> would be bare
> > trace to bare trace. Why would this spacing need to be
> greater than bare
> > pad to bare pad (the A6 rating)?
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