I have an existing situation where there are empty conduits that enter into a panelboard from below. There is 3" between the concrete floor and the bottom of the panelboard. I need to reuse this conduit, but need to feed it to another panel. Can I route the conductors through the panel and route a new conduit from the top of the panel to the location of the new panel? The question is, can a panelboard be used as a pull box?