I'm just beginning to look the situation over in preparation for some electrical work and would like to add two or three more circuits through my panel. From the outside of the box it appeared that it shouldn't be a problem since there are 9 more knockout plugs for additional breakers. Then I removed the cover and found that the central bar for the neutral connection of the breakers doesn't extend the full length of the panel. Not what I expected. Can someone explain the reasons for this? Can the neutral bar be extended somehow? Should I just figure on using the piggyback breakers to gain the additional circuits, or are those still considered acceptable these days? I've attached a couple of pics, for what it's worth.