1
\$\begingroup\$

Probably this has been asked before, I am not clear about regulations (standards).
I have a chipset close by 220VAC mains pins, impossible to move away due to other mechanical constraints.

Actually, I have ~2mm clearance. The PCB will be coated with solder mask (related to this post)
What is the right PCB clearance when using mains (220VAC)?

What I can do is to have a slot in PCB, to isolate more from pins to mains.

Other ways, I have to stack 2 PCBs, one containing mains connector and other, low voltage.

If anyone knows who precise regulates this, what standard, maybe there is a chance to use a single board.

Tnaks in advance,

enter image description here

\$\endgroup\$
7
  • \$\begingroup\$ The standard is listed in the question you linked and, it is downloadable (earlier versions). \$\endgroup\$
    – Andy aka
    Commented Dec 19, 2022 at 15:21
  • \$\begingroup\$ hmmm.. just a picture on my side, no link to download \$\endgroup\$
    – yo3hcv
    Commented Dec 19, 2022 at 15:22
  • \$\begingroup\$ I don't see a standard in the link, and the caption in the image just says IPC-2221, an outdated industry (non regulatory) standard. \$\endgroup\$
    – Tim Williams
    Commented Dec 19, 2022 at 15:34
  • \$\begingroup\$ The X distance is 32.283 mils. But isn't that the distance between the center of the pins/pads, and not the spacing? \$\endgroup\$
    – SteveSh
    Commented Dec 19, 2022 at 15:55
  • 1
    \$\begingroup\$ IPC 2221 A \$\endgroup\$
    – Andy aka
    Commented Dec 19, 2022 at 17:07

1 Answer 1

Reset to default
3
\$\begingroup\$

Depends on product and market. For a general starting point, consider IEC 62368-1.

Beware: depending on process, and standard being met, solder mask may not count as insulation. It is prone to form thin films, or pinholes. Standards may require an inspection process, which as far as I know, fabs don't do, or not usually.

You can almost certainly do that with potting, but that's probably a lot of work/cost. Another possibility is a milled PCB slot, which increases creepage distance but not clearance; a strip of polyester or FR-4 could be glued into the slot to enforce more of both.

Also, you may simply not want to do it anyway: consider the effect of mains EFT, and the capacitance between pads. Transients could disturb readings, or even induce device crash/reset/latchup.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.