Electrical Panel Knock-Outs
The electrician will remove the knock-outs as required for the breakers. No more, no less. But over the life of the home, renovations happen. Things are added and things are removed. If circuit breakers are removed, the empty slots should be covered up with filler plate covers. Otherwise, it is possible to poke a finger or a tool into the open slot and touch the electrical buss inside the panel. Covers are inexpensive and should be purchased to match the brand of the panel.
These covers are easily snapped into place without having to remove the front panel of the breaker box.