I don't believe the large single wire is a fusible link. I could be wrong but I don't think it is. So, All you would need to do would be to splice the two smaller wires to the large wire. I believe that is acceptable since you are going from one large lead to two smaller ones.
The single wire is connected to two wires that have a fusible link and each of them have two different gauge wires on each side of the fusible link. Sorry if I made that confusing earlier.
