Re: Minimum clearance for 230V AC.

On 03-10-2024 14:05, Chris Jones wrote:

On 3/10/2024 8:11 pm, Pimpom wrote:

What's the minimum surface clearance you consider adequate for 230VAC, on FR4 without slots or added creepage? Forget about IPC-2221 unless you base your layout strictly on it.
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Personally, I try to maintain 3mm edge-to-edge between tracks and pads, more if space permits. What do you think?

 The distance along a surface is called creepage in the standards.
 The required distance depends on whether the insulation is supposed to be single insulation (functional, basic or supplementary) or double insulation (reinforced insulation).
 Basically, if the insulation failing ought not to kill someone because the part that would become live is either protectively earthed or separated by supplementary insulation from the user, then a smaller creepage is allowable.
 If the insulation failing could immediately give someone a shock because there is no protective earthing or supplementary insulation, then a larger creepage distance is required.
 The exact distances required in different standards tend to be different, though I think a lot of different products that used to be subject to different standards have recently been grouped into one set of standards, IEC62368-1.
 There are some tables here:
https://www.powerctc.com/en/node/4757
 I think you are going to come up with something like 2.5mm for basic insulation and 5mm for reinforced, but you should check carefully what the standards say, and for some classes of equipment it can be much more, like 6mm or 8mm.
 

For <230V working voltage supplied ac equipment 3mm Basic insulation and 5mm reinforced is typical. Notice that often clearance is larger distance than creepage. Creepage is also easier to handle, since you can add slots. You can't do that for clearance