For all the electrical experts, I am blowing the fuse over and over on my lights. I think the ext cord ( plug says c 10 whatever that means) is too small as the place where the fuse is blowing is at that 1st connection. Also, I stopped at 4 strings because the 5th one was blowing it too. Is it too many strands? I am using the old school 9c strings. Please help!!!