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I have a 'guitar effects power supply' built to supply 9v/12v/18v power to 🎸 guitar effects pedals. It is powered using a IEC 60320 C13/C14 power receptacle and cable.

After using this device for the majority of the day, I finally turned off the unit by removing the C13/C14 power cable from the device. When the cable was still half-way in (as I removed it in a 'skewed' fashion) I heard arcing, saw sparks, heard a pop and smelled some 'magic smoke' escape. From this point on my device was dead! (Luckily, it's fairly new and it's got warranty!)

The device manual says nothing about hazards of plugging/unplugging at the C13/C14 connectors. I've seen other C13/C14 devices like a guitar amplifier (and I believe some PC power supplies) have manuals that warn to "always plug and unplug the device at the wall".

Questions:

  • May plugging/unplugging powered C13/C14 cables into unpowered devices cause arcing that can damage devices?
  • May this cause over-voltage conditions in badly designed power supplies? (as in: damage to the devices the powersupply was feeding)
  • Was this user error? Should I always plug/unplug devices from the wall?
  • Does IEC 60320 even say anything at all about arcing situations or usage scenarios like this?

I think I may have once heard an old adage of "always connect data cables to devices first, then connect power". I've got suspicions it might be true after all...

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    \$\begingroup\$ It should not make a difference from which end you unplug the mains cable. But removing it slowly is a bad thing anyway so it's not halfway in and making an intermittent contact which arcs and sparks. For the record, C13 and C14 are not "kettle" connectors either, while similar a kettle has a different type of connector and C13/C14 are not rated for kettle use. Which device it was? \$\endgroup\$
    – Justme
    Mar 24, 2021 at 5:31
  • \$\begingroup\$ C13/C14 may be incorrectly called a "kettle" connector. So I did just that, my bad. Rest assured that the socket/plug are C13/C14. The device was a Harley Benton PowerPlant ISO-10AC Pro. \$\endgroup\$
    – Xunie
    Mar 24, 2021 at 15:09
  • \$\begingroup\$ If it's well designed it should not cause a failure. If. \$\endgroup\$
    – Spehro Pefhany
    Mar 24, 2021 at 15:18
  • \$\begingroup\$ @Justme It may well make a difference because the amount of high-power RF noise from the arc will be much reduced by the inductance and capacitance of the cord. Power cords typically aren't very efficient RF cables. \$\endgroup\$
    – TooTea
    Mar 24, 2021 at 16:07

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