A rat moved into the crawl space under my kitchen (an extension to the main
house) and chewed the white outer sleeve off of three 14-3 cables. Each
cable supplies power to a single outlet. The cables run from the main panel
in the basement, into the crawl space under my kitchen, and about half way
into the kitchen and over to the base of a wall. They then go up the wall,
and over the ceiling and down another wall to the outlets.

I am replacing the damaged cable with new 14-3 and routing immediately from
the basement up an inside wall to the kitchen ceiling avoiding the crawl
space completely; although the offending rat is now dead, I'm sure another
will show up some day, and I do not want to have to replace these wires
twice.

My problem is that it would require a great deal of work to replace the
entire runs from the panel to the outlets. I can get the cables from the
panel into the kitchen ceiling. I can even access each of the 3 damaged
wires from where they enter the ceiling to where they go down the wall to
the outlets. However, without ripping out the parts of the 2nd story wall
(above the kitchen wall with outlets) I cannot pull out the old wires, let
alone feed in down new ones. The reason is likely that the holes drilled
through the wall plate and header are probably quite small and the 14-3 wire
is very tightly inserted.

I do however have an unused junction box in the ceiling of my kitchen so it
would very convenient to upsize the junction box to a square 42 cubic inch
box and splice the old an new wires at this location. Is there any problem
with this approach? I did the calculations and a 42 cubic inch junction box
is large enough for three 14-3 in and three 14-3 out (6 cables in total). I
also don't mind having the junction covered and visible on my kitchen
ceiling since there has always been one there.

Thanks in advance for any comments or advice.