Hi I live in Sydney and I am getting my home power board upgraded as I currently have the old ceramic fuses. I am getting conflicting advice from electricians that I need sorted out. One, apparently very experienced electrician, said that the maximum 3 phase fuses I can have is 50 amps x 3 because my power is underground from the street. Apparently the cables get hotter underground and can burn out if it is a higher load than 50amps. He said 63 amps is ok if the wires to the house were overhe ...