I have a load that I'm powering from a 60W AC-to-DC converter that has a stated cold start inrush current of 30A@120V:

https://www.meanwellusa.com/upload/pdf/IRM-60/IRM-60-spec.pdf (the 15V output ST model)

I'm concerned this will trip common 15A breakers, so I'm looking for a simple way to limit the inrush to about 10A. I'm not concerned with power efficiency so I'm looking at a NTC thermistor in series with the supply.

Design guides I've read indicate it's important to consider the capacitance of the power supply you are trying to limit - I don't see this specified anywhere in the datasheet linked above, can it be calculated (or estimated) from any of the supplied values?

  • 2
    \$\begingroup\$ My question is why do you think any extra limiting is necessary? Look at how much is the inrush current of a typical computer power supply. Do they trip breakers when plugged in? \$\endgroup\$
    – Justme
    May 26 at 18:10
  • \$\begingroup\$ I had an issue with it tripping a breaker, but I haven't yet confirmed the exact specs of the breaker (probably 15A) or if the breaker is faulty. The supply works fine on some 15A breakers from my testing. \$\endgroup\$
    – davegravy
    May 26 at 18:20
  • 1
    \$\begingroup\$ The screw terminal model is likely supposed to be directly connected to mains plug wires. If it trips breakers, the supply might be faulty, the breaker nearly overloaded or faulty, or the wiring is incorrect. It may also depend on which specific type of breaker you have. It might be best to post more details. \$\endgroup\$
    – Justme
    May 26 at 18:32
  • \$\begingroup\$ 30 A inrush should be no problem on a 15 A breaker. \$\endgroup\$
    – winny
    May 26 at 19:28
  • 1
    \$\begingroup\$ Fuses usually blow by their i^2t ratings. Do you have any waveform from which this can be estimated or calculated? \$\endgroup\$ May 28 at 15:40


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