jango
Senior Member
I am working on a residential project which originally had planned for a 200 amp single phase electrical service. I am now being asked to upgrade the service to a 400 amp single phase sevice. The AHJ is asking for a Single Line Diagram of the electrical distribution as part of the proposal package for the permit. Is this normal and can someone refer me to a website where a Single Line Diagram for a single phase (400 amp) would apply? I was under the impression that a Single Line Diagram is used for three-phase systems. Any help on this would be greatly appreciated. Thanks!