So I'm curious why this panel is configured in such a way that although there are positions on the panel for 4 additional breakers, the hot bus bars do not extend far enough down to actually make use of those remaining 4 circuits/breaker positions.
If you look at the pictures with the panel cover on you will see open spots 17,18,19 and 20 - however with the panel cover off the hot bus bars do not extend far enough so breakers in those positions (17,18,19,20) could make contact.
The plastic backing behind the hot bus bars extends far enough, however the actual metal bars do not extend beyond position 15/16 on the panel. This panel was installed by an electrician when the house was built.
Is this normal or are the bus bars not correct for the panel enclosure?