Hi:

After a main service disconnect the electrical panel located 80' away is considered as a sub-panel ?

Thanks

Does that panel have the neutral bus separated from the ground bus?

They should be separated in a sub panel, that doesn't mean it is a sub panel.

For the purpose of your question, which I will assume is regarding grounding, and the separation of the neutral and equipment ground beyond the Service Disconnecting Means, yes, the Main panel will be connected the same as a "subpanel", as being a sub, or below, or beyond, the Main.

Keep in mind, there is no technical term "subpanel" listed, defined, or used in the actual National Electric Code text. This is a trade term created by electricians to indicate a panelboard that does not contain the Main Service Disconnecting Means.

We know that the grounding of the neutral and bonding to the equipment grounding conductor happens at or before the Main.

We all know what each other is talking about, and have tended to "create" abbreviations and/or slang for terms, equipment, etc. These terms then get out to laypeople, who at times, may used them in the wrong context.

So, if you are referring to your "main" panel as a "subpanel", in the context that the neutral must be insulated and isolated from any equipment ground, then you are correct in your thinking.

Thank tkrussell , that is exactly the picture.

Now, I'm planning to run 3 # 1/0 XHHW,AL, and 1 # 6 THHN, CU on 125 amp, 240 v service, through a 1 1/2 PVC SCH 40 attached along the wall from 125 amp main disconnect to 125 amp main lug panel. Is anything wrong with this on commercial work ?

#1/0 Al is only good for 120 amps, using the 75Deg C column of table 310.16 of the NEC, so need to use #2/0 Al for a 125 amp feeder.

The 1.5" PVc Sch 40 can handle 4-#2/0 XHHW Al, so the conduit size is good.

Assuming the conduit run will be horizontal on the exterior of the building, expansion couplings will be needed, due to the expansion of PVC, esp in areas the outdoor temp gets hot.

Review:http://www.carlon.com/Installation_Training/IT-NEMAEXJTA.pdf

This info is also found in Article 352 Nonmetallic Conduit, along with supporting interval of every 5 feet for 1.5" PVC conduit.

I assure you, strapping even at every five feet, the conduit will sag between supports and end up looking like a roller coaster. While horizontal runs are allowed, most good electricians will not run PVC any great lengths horizontally, as there will be complaints of the appearance.

The choice is yours, as long as you heed the warning.