U.S. outlets are grounded mostly, unless they're older construction. We do still sell some non-grounded extension cords because lots of appliances (toaster, co

U.S. outlets are grounded mostly, unless they're older construction. We do still sell some non-grounded extension cords because lots of appliances (toaster, coffee maker, lamp) have non-grounded plugs. I have no idea what they're talking about with regards to sparks. If the appliance is switched on while you're plugging it, maybe?