Fusing Current Calculator
Calculate PCB trace fusing current using Onderdonk equation
Trace Parameters
Warning: Operating at or near fusing current will destroy the trace. Always include safety margins.
Duration of fault current
Fusing Analysis
Fusing Current
2.6 A
@ 1s
Safe Operating
0.6 A
25% of fusing
I²t Rating
7
A²s
Max Surge
1.9 A
75% of fusing
Cross Section
18
circular mils
Time to Fuse
0.07 s
@ 10A
Width for 10A
39.0 mil
to fuse in 1s
Very low fusing current - Fine pitch traces
Fusing Current Reference (1oz copper, 1s)
| Width (mil) | Area (cmil) | Fusing (A) | Safe (A) |
|---|---|---|---|
| 5 mil | 9 | 1.3 A | 0.3 A |
| 10 mil | 18 | 2.6 A | 0.6 A |
| 15 mil | 26 | 3.9 A | 1.0 A |
| 20 mil | 35 | 5.1 A | 1.3 A |
| 30 mil | 53 | 7.7 A | 1.9 A |
| 50 mil | 88 | 12.8 A | 3.2 A |
| 100 mil | 175 | 25.7 A | 6.4 A |
Onderdonk's equation is most accurate for times between 0.001 and 10 seconds. For longer durations, steady-state thermal analysis should be used instead.
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