First time building an AC control system complete with motors, PLC, sensors, power supplies. All this is sourced from a 220VAC outlet. I have calculated the total current draw of all motors, powers supplies, etc, to be about 38A at full load. What I am concerned about is my 2000A inrush current calculation. Would it be safe to enable the 220VAC line to the control system when connected to a 220VAC wall outlet that can output 60A? Is this kind of inrush current value normal for industrial control systems, therefore it is alright and outlet circuitry can safely handle this event?

  • \$\begingroup\$ Show calculations and assumptions. What does I^2R tell you with R= source + load impedance. Or ratio of R for source/load? Also consider inductance with cable at 1 uH/m \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Sep 25 at 22:58
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    \$\begingroup\$ I don't think you can get 2000A of inrush current, and it would probably trip most breakers, you'd have to have a 2000A breaker. \$\endgroup\$ – Voltage Spike Sep 25 at 23:02
  • \$\begingroup\$ 2 servo drives (main circuit) - 44A inrush each \$\endgroup\$ – BlueSock Sep 25 at 23:16
  • \$\begingroup\$ 30 power supplies - 60A each, 1 PLC rack - 12A inrush \$\endgroup\$ – BlueSock Sep 25 at 23:18
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    \$\begingroup\$ You can edit your question to include these infos on the question, not on comments. Its easier to follow for future readers. \$\endgroup\$ – Wesley Lee Sep 25 at 23:57

In general, a 60 amp branch circuit should be constructed using components; conductors, connectors, and outlet devices that will be protected by a 60 amp circuit breaker of a type that is suitable for that service. All branch circuit components should be certified by an independent testing laboratory in that regard. The standards that apply to the distribution components should tell you what they can withstand. It may be easier to examine the curve for the circuit breaker. If the worst-case instance of short term current will not trip the circuit breaker, the distribution components should be ok.


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