Hi,
What answer do you expect?
Maybe you expect a reply "2.5mm is fine"
But the PCB still will fail.
Maybe you expect a reply "5.0mm is fine"
You change the PCB layout, but maybe the PCB fails again. What do you gain?
I recommend to look for a good documentation. It may be hard to read, but it explains the details. Details that you don´t see now.
"xx mm trace width" seems to be a simple answer. But there are a lot of parameters to consider.
Some of them are:
* copper thickness
* trace length
* outer layer, inner layer
* coating
* current waveform
* PCB material
* ambient temperature
* additional sources of heat
* heat preading
* air pressure
* regional (country) safety regulations.
* ...
Beacuse of the complexity of the heating problem, there are many documents/tables/calculators. Some are more detailed than others. Some are focussed on the PCB material, some are focussed on heat spreading.
But in the end.... if you feed the formulas with YOUR parameters..I think most of them will give about the same result.
Did you try this?
Klaus