MST Kruskal's algorithm in Python
Why do you assume this code is limited to 10 vertices? This code comes from: http://www.geeksforgeeks.org/greedy-algorithms-set-2-kruskals-minimum-spanning-tree-mst/

But you have an error in use:

 g = Graph(14)


Defines a graph with 14 vertices but then you used 0-14 which is 15 vertices. Either use:

 g = Graph(15)


Or remove all the edges with vertex 14.