Motor PT

[kwired]

I still don't see how identification of system and phase fits in with what 90.1 says.

Can it be a good design practice? Yes.

Sometimes it really doesn't matter that there be that distinct of identification. If it isn't a grounded or equipment grounding conductor, both of which have long had identification requirements, don't touch it unless you verify it is not energized:roll:

 

[GoldDigger]

I still don't see how identification of system and phase fits in with what 90.1 says.

Can it be a good design practice? Yes.

Sometimes it really doesn't matter that there be that distinct of identification. If it isn't a grounded or equipment grounding conductor, both of which have long had identification requirements, don't touch it unless you verify it is not energized:roll:

And don't connect a new load to it until you have verified the voltage!

 

[don_resqcapt19]

I still don't see how identification of system and phase fits in with what 90.1 says.

Can it be a good design practice? Yes.

Sometimes it really doesn't matter that there be that distinct of identification. If it isn't a grounded or equipment grounding conductor, both of which have long had identification requirements, don't touch it unless you verify it is not energized:roll:

The original rule only applied to multi-wire circuits and that can be a safety issue where you are making modifications.
The 2002 code said this:

210.4(D) Identification of Ungrounded Conductors. Where more than one nominal voltage system exists in a building, each ungrounded conductor of a multiwire branch circuit, where accessible, shall be identified by phase and system. This means of identification shall be permitted to be by separate
color coding, marking tape, tagging, or other approved means and shall be permanently posted at each branch-circuit
panelboard.
210.5 Identification for Branch Circuits.
(A) Grounded Conductor. The grounded conductor of a branch circuit shall be identified in accordance with 200.6.
(B) Equipment Grounding Conductor. The equipment grounding conductor shall be identified in accordance with 250.119.

The 2005 code deleted 210.4(D) and said this. (note that the conductors were only required to be identified by system)

210.5 Identification for Branch Circuits.
(A) Grounded Conductor. The grounded conductor of a branch circuit shall be identified in accordance with 200.6.
(B) Equipment Grounding Conductor. The equipment grounding conductor shall be identified in accordance with 250.119.
(C) Ungrounded Conductors.
Where the premises wiring system has branch circuits supplied from more than one nominal voltage system, each ungrounded conductor of a branch circuit, where accessible, shall be identified by system. The means of identification shall be permitted to be by separate color coding, marking tape, tagging, or other approved
means and shall be permanently posted at each branch-circuit panelboard or similar distribution equipment.

The 2008 restored the requirement that the conductors be identified by phase and system.

210.5(C) Ungrounded Conductors.
Where the premises wiring system has branch circuits supplied from more than one nominal voltage system, each ungrounded conductor of a branch circuit shall be identified by phase and system at all termination, connection, and splice points. The means of identification shall be permitted to be by separate color coding, marking tape, tagging, or other approved means. The means of identification shall be documented in a manner that is readily available or shall be permanently posted at each branch-circuit panelboard or similar branch-circuit distribution equipment.

 

[MiElectrician]

One of my first jobs as an electrician was helping a guy land six parallel 350's in a custom made pecker head for a large motor. Took two days to do it and as we're getting done the engineer comes up and says he's 99% sure it's going to spin backwards. we would've had to tap one of the phases to switch them. The master electrician said that the primaries got landed backwards and everything in the building runs backwards or something. Long story short, it worked the way we installed it, but it would've been close to a grand in labor and taps if we had to change anything.