I have a 5 way plug socket thingy with "surge protection" built in. When I plug my laptop psu (or phone charger) into it and it is already switched on at the wall I often see an spark. It seems to work fine however. Whats the deal?
I read the following but I am skeptical:
"If you are plugging/unplugging under load it means that there is some abrupt energy change causing a spark. Inductors (motors) try to prevent changes in current. So if you unplug one while on it will spark. Capacitors try to prevent changes in voltage. So if you plug something in with a switchmode supply, it will spark as the input capacitors try to quickly charge."
Is this "normal" or expected sometimes? i mean my laptop uses a switched mode psu - I just want to be sure my laptop is in no danger!!