I am replacing an old Jenn-Air stovetop, with a much newer (but also used) Jenn-Air stovetop. Both have 4 burners with a downdraft blower. But, the newer stovetop's built in junction box is about 2 feet farther away...so I'm going to have to extend the wiring to reach the new stovetop. The house has 8 gauge running straight from the breaker box all the way to the stovetop's built in junction box (no other junctions currently in between). I can add a junction box within the cabinet, and add the new 2-3 foot extension to the new stovetop, and should be simple, right?). But I noticed...BOTH the old and new stovetops have 12 gauge coming out of the actual appliance. Also, according to labels on both old and new stovetops are 7KW. Per the paperwork found online, the recommended minimum wiring should be 8 gauge, 40 amps. I just find it strange that the appliance itself has 12 gauge wire, but recommends it be connected to 8 guage in the house. Is that typical and normal? All that said, then does it really matter if the 2-3 feet of wiring that I add is 8 guage, or 12 guage? Either way, it will have BOTH 8 and 12 guage wire along the run. Lastly, if buy 3 feet of wire sold by the foot at a large warehouse store...what specific wire do I look for?

I have a friend who owns a storage place for fish. He has near 50 freezers up there. He called me and said that he has recently changed all wires and installed a new panel board. Suddenly after the new installation the panel board got hot. Why is that? Any suggestions?