I need to replace a subpanel and the old one is smaller than the new one.
The old one is already maxed out with minis and has more than one circuit
fed from one half of the mini (more than one wire under each screw). there
is no more room in the closet for another subpanel. I purchased a bigger
panel with more slots, but most of the wires are too short now to reach the
new breaker slots. Can I just lengthen the wires using wirenuts to make them
reach the new breakers legally? This is the only way I can think to do it
without having a bunch of junction boxes up in the attic to feed the new
panel.

Thanks