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Good Day, I am thinking the opposite from this last entry (JM) but have no background in electrical theory. I have a lot of appliances I plug/unplug w/a little box in-line (I assume "transformer"). Some of the appliances are expensive (e.g., laptop computer).

Is it better for my appliance to plug into the wall receptacle and then into the appliance or the opposite?

  • Hello, and welcome to Home Improvement. It's a little hard to understand your question, even after @manassehkatz's work. Would you put a bit of time into cleaning it up? And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Jul 15 '19 at 14:31
  • that's Ok, 'short termer' here. Got what I need, ppl were very gracious - as U have indicated I have trouble expressing my self (got learning disability directly effecting all this) plus don't have the ele. theory, vocab & understanding to wrd the Q well. Thanks for the offer Dan ! – Chad Jul 22 '19 at 15:29
  • Voting to close. OP didn't clarify and hasn't been back. The question appears to be about usage anyway. – isherwood Aug 7 at 21:11
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I have never heard it matters whether the "power supply" (converts mains ac to lower voltage DC) is plugged into the appliance first or into the mains electric receptacle first.

A theoretical speculation could be that the power supply would generate damaging transients when it is first plugged into the mains power, but if they would do this, then when the power was interrupted it would damage the appliance.

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    I always plug the laptop power brick into the supply first, then plug the charging lead into the computer... – Solar Mike Jul 14 '19 at 15:02
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    I have seen a very short duration blue spark at the receptacle & wish to avoid similar at the laptop or appliance. Am thinking of durability and expense... – Chad Jul 14 '19 at 15:56
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    Don't worry about a small blue spark, unless you are in a chemical plant. I get that on cell phone chargers. That is simply inrush current and the luck of favorable lighting that allows you to see it. – Harper - Reinstate Monica Jul 14 '19 at 17:12
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    To be clear, inrush current is a characteristic of the device, usually the power supply charging capacitors, or other radically nonlinear things. Your laptop's power brick may have this characteristic, but your laptop may not. – Harper - Reinstate Monica Jul 14 '19 at 17:19
  • My understanding has always been to first plug a charger into the device before you plug it into the power source. Otherwise the voltage in the cord could cause an electrical arc and fry the electronic device. I had this happen on a laptop once. My wife's electric bike specifically states that when charging the lithium iodide battery to plug the cord into the battery first and then connect it to power. You do the reverse when unplugging it. Maybe I'm missing something but it's always made sense to me. – HoneyDo Dec 12 '19 at 0:20

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