Question regarding a "Single Line Diagram"

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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!
 

billsnuff

Senior Member
I spend my days in a factory, only do minor residential, permitted naturally, but not required in my little map dot.

Hopefully others will chime in..............
 

rcwilson

Senior Member
Location
Redmond, WA
A Single Line Diagram or a One Line Diagram or a Riser Diagram shows how electrical power equipment is interconnected from the utility service to the end loads. It can apply to three phase or single phase power systems. Notes or descriptions on the drawing describe ratings of the equipment, voltage levels, short circuit currents and other pertinent data.

The one line sketch is a concise method of explaining to an inspector, plan reviewer, or utility what the proposed electrical system looks like, complete with all required equipment sizes and ratings.

On simple systems it's not needed. On larger systems it is essential for understanding what is being proposed.

Sketch one up.
 

cadpoint

Senior Member
Location
Durham, NC
Yes, lay it on it's Side...add or subtract to suit. :cool:

Label the panels fully and state your wire and type of the circuit runs.
 
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buzzbar

Senior Member
Location
Olympia, WA
Occupation
Electrical Contractor
In my neck of the woods, a riser diagram is required for anything 400A or higher, regardless of whether it's 3-phase or single phase.
 
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