The closest thing I can think of is a disconnect. These basically are a box with a block that can be removed/flipped, generally seen on air conditioners. If you just took the block with you this would effectively stop them. If your kids are the kind to cause mischief, you can also padlock most of these styles of disconnects (and other styles of shutoffs).
If you have ever seen a "welder outlet" in an industrial setting, the switchbox/disconnect associated with it is basically what you are looking for. Has a handle you can lock out with a padlock