Single Line Diagram

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My POCO has requested a single line diagram for the new 3 phase 400 amp service I intend to install.
I have never done one before.
In the past we just install using one of the methods outlined in their blue book.

What information are they looking for?
Just a block diagram showing the lateral, meter channel, building wall
and two 200amp parallel load centers?
 

Jljohnson

Senior Member
Location
Colorado
They will most likely want to see a feeder schedule and an arc-fault calculation as well, I would ask them directly EXACTLY what info needs to be included on the one-line. Around here (Colorado) the building dept. is typically who asks for this type of thing and they demand an engineer's stamp as well.
 

480sparky

Senior Member
Location
Iowegia
This is probably far more complicated than what you're doing, but is this what they're looking for?:

onelinediagram.gif
 

inspector141

Senior Member
Location
Westminster, MD
single Line Diagram

single Line Diagram

A one line feeder schedule for a service should include:

1.Utility Company transformer location (may require fault current calc's)
2. Plan and elevation view layout of the electric room or the space the service will be installed showing electrical equipment.
3. All wiring methods, wire sizes, wire type, including equipment grounds and grounding electrode conductors.
4. location and size of service disconnect and meter.
5. location and size of feeder panel if used.
6. All applicable notes.
7. Key plan
8. Engineer seal if required. We accept signed drawings from a licensed electrician if design is simple and done professionaly.

I hope this helps.

Marty
 
That helps. I?ll give it a shot and see what I can get away with.

I?m curious what point these are required.
Do you do them for a home?
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
480sparky said:
No. A service calculation is all that would be required.

Possibly, if there are subpanels. But I'm not sure why the POCO would have any intrest in that. Our POCO won't inspect anything past the service. They could care less what the premesis wiring is like. I guess they don't want to butt heads with the local inspector.
 

wirenut1980

Senior Member
Location
Plainfield, IN
When I was doing distribution design for a POCO, I would sometimes ask for a one line diagram and panel schedules if I was not sure what size transformer to install (e.g. if there was not sufficient information from a similar type customer). I would also look to see if there were any large loads being installed that might be of interest in terms of voltage flicker, or harmonics, etc. I could care less about most of the information listed by inspector, however it is important for others. :grin:
 
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