Is there any chance that a 30-watt device's circuit board could arc across a 1mm gap to aluminum? Specifically 12v by about 2.5 amps.?
The aluminum would be a flat plate no closer than 1mm over the whole surface of the circuit board.
The aluminum would be a flat plate no closer than 1mm over the whole surface of the circuit board.
qrk
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Depends.
Normal operation, 1mm gap is good for 150 to 170 VDC and VACpeak according to IPC-2221. At 12V, this is safe.
If you vaporise the copper traces due to a current overload condition, the plasma can support a fairly low voltage arc. DC arcs can be hard to extinguish, AC arcs often extinguish themselves. It takes quite a bit of current to vaporise a copper trace.
I've seen this happen on a 150VDC power source. It coated copper all over the cabinet and circuitry and caused arcs in areas that were 50+mm away from the original failure. The initial failure probably dumped on the order of 100k to 1000k Amps.