210.5(C)(1)&(3)

[lefty]

I interpreted this to belong in a building where you have as an example 480/277v and 208/120v system in a building. The AHJ interpreted it that it includes all panels unless your panel only has 120volts to ground or similar circumstances. Specifically what happened was a dwelling panel with 240/120v single phase typical of most dwellings, was to interpret it needed the label identifying the colors of the wires. He used this code reference 210.5(C)(3) as his basis for argument. My argument was that was it did not apply to residential, it was for commercial, institutional, and industrial establishments. Where two different systems are used in conjunction with a transformer, for example a 480/277-208/120system. Not on a single phase system in a dwelling. He stated that a house has two different systems 240/120,:blink: I told him to go get some education and then come back when he grew up:rant:

I told him if he did not pass it, I would send a letter, describing the situation to the surrounding AHJ's in the state and the State Inspectors describing what happened here.:slaphead:. That way they would have some comic relief at their next convention.:thumbsup:

Okay let us hear your opinions, or better yet, some better comebacks.

 

[kwired]

(1) Application

Where the premises wiring system hasbranch circuits supplied from more than one nominal voltage system, each ungrounded conductor of a branch circuitshall be identified by phase or line and system at all termination, connection, and splice points.​

​

You are absolutely correct. 120/240 derived from same core and coil is one nominal voltage system.

120/240 derived from three separate coils all interconnected is also one nominal voltage system.

If a building is supplied by three phase but only has one nominal voltage system there is no requirement to identify system and phase at every place mentioned. It can be useful on three phase but is not required, on single phase it doesn't really have a lot of usefulness to identify line 1 and line 2 throughout the building. Neutral must be identified no matter what.

 

[George Stolz]

My argument was that was it did not apply to residential, it was for commercial, institutional, and industrial establishments.

I would take issue with throwing around the words "commercial" and "residential" - if a residence had two nominal voltage systems, then the same rules apply.

Now, that said, you are correct that when there is one nominal voltage system in a structure, then the conductors do not have to be identified. You could have shown him 220.5(A) to support your position:

(A) Voltages. Unless other voltages are specified, for purposes of calculating branch-circuit and feeder loads, nominal system voltages of 120, 120/240, 208Y/120, 240, 347, 480Y/277, 480, 600Y/347, and 600 volts shall be used.

Each of the underlined are "nominal system voltages", they are all systems, and 210.5 is referring to nominal voltage systems. The inspector was way off base.

 

[jwelectric]

In my home I have two voltages 120/240 and 24. The 24 volt system is in my air handler. Do I need to post these labels?

I don?t have a door bell as one is not needed, the Chihuahuas let us know when someone arrives way before they make it to the door.
:rotflmao:

 

[George Stolz]

In my home I have two voltages 120/240 and 24.

Suppose that was a doorbell - I wonder if we have two "nominal voltage systems" then? :huh:

 

[guschash]

Are we talking voltages coming into structures and labeling the panels that those voltages go to. I don't think 24v after the panel is what the intent of the article is saying. Just my thought.

 

[kwired]

Are we talking voltages coming into structures and labeling the panels that those voltages go to. I don't think 24v after the panel is what the intent of the article is saying. Just my thought.

If that were the case this would not be too big of a topic. Most places that have both 480/277 and 208/120 and or 240/120 only have 480/277 supplying the building. Other voltages are separately derived from that and are separate systems.

You must also remember that if it is 24 volt there is a good chance it is a art 725 application. It still may need to be distinguished from power circuits somehow, not totally sure, most of the time it is just because different conductors/cables are used.

 

[guschash]

I thought we talking 120/240 residential?

 

[cowboyjwc]

I would agree that if you only have one voltage then you don't need the signage.

Now remember once you've posted those colors you need to stick to them and can't be adding purple or pink later on down the line.

 

[kwired]

I thought we talking 120/240 residential?

I don't think we are.

First sentence of OP:

I interpreted this to belong in a building where you have as an example 480/277v and 208/120v system in a building

.