Is this AC Phase arrangement correct?

[jap]

Can one of you post the rule that indicates

Because 210.5(C) says the conductors have to be identified by phase and voltage where there is more than one voltage system in the building. the code does not assign a specific color for the identification by phase and voltage. The installer does that, but it must be the same through out the building.

You have identified the different phases and voltage of the 480v by Brown, Or, Yellow and the 208v as Black Red Blue,,,

But,

This does not say that Brown and Black are specifically for A Phase, Orange and Red are specifically for B phase or that Yellow and Blue are specifically for C phase.

Therefore how could swaping the Brown, OR, Yellow on the bottom of a disconnect to Yellow, OR. Brown be a violation?

JAP>

 

[jap]

I think I see what you're getting at now.
and,
Yes,, this rule is very abused in that case.

JAP>

 

[don_resqcapt19]

Don,

Any particular reason why they rejected the exception? IMO this entire code section needs work.

From the feedback I received from some panel members, the IAEI saw the exception as a "serious" safety issue, and often the CMP will be swayed by the IAEI.
There is no safety issue. The only reason the identification by phase and voltage was put into the code was to help prevent the overloading of a the neutral of a multiwire circuit. My exception was clear that it only applied to branch circuits that supplied line to line loads.

Public Input No. 1374-NFPA 70-2017 to add new Exception #2.
Exception No. 2: Ungrounded conductors of three phase branch circuits serving line to line connected utlization equipment shall not be required to be identified by phase.
Statement of Problem and Substantiation for Public Input
In the 2014 and earlier editions of the NEC, Article 210 did not include motor branch circuits and the requirement to identify the motor circuit ungrounded conductors by phase and system did not apply to those conductors. The scope of Article 210 was expanded in the 2017 edition to include motor branch circuits. This requires that the ungrounded motor branch circuit conductors be identified by phase and system and requires that any change in motor rotation be made in the motor junction box, not in the motor starter as have long been the common practice. The proposed exception would permit the motor rotation to be changed at the starter and not in the motor junction box. It is much quicker and less costly to change the rotation in the starter than in the motor junction box, especially in industrial applications where the motor terminations are insulated with rubber and plastic tape. It could take an hour or more to change the rotation at the motor junction box for a large motor, where changing the rotation at the starter would only take a few minutes. The original requirement to identify the ungrounded conductors by phase and system only applied to multiwire circuits, and there are good reasons for that requirement, but those reasons do not apply to three phase branch circuits serving line to line connected loads. The proposed exception leaves in place the requirement that these conductors be identified by system.
Committee Statement
If the phase rotation is changed at the motor, there is no need to re-identify the branch circuit wiring to the motor. There are other locations that can be used to change the phase rotation of a motor left to the discretion of the installer. There is no substantiation given to raise a safety concern that this labeling cannot occur at other locations used to change phase rotation.

NEMA submitted a similar proposal in the 2014 cycle.

Public Input No. 597-NFPA 70-2014
Exception No. 1 - Where motor loads are served that may require a phasing adjustment for rotation after initial installation.
Statement of Problem and Substantiation for Public Input
In many cases after a motor load is fed and the inspection is complete the rotation of the motor may be incorrect. Under the current rules the installer would be required to re-identify the conductors after the phasing is changed for motor rotation. This could create a endless amount of change to an already designed and installed system. There is no additional safety hazard by allowing this portion of branch wiring be identified differently, as the individuals repairing or troubleshooting these types of installations.
Committee Statement
The exception is not needed because proper phase rotation can be achieved while still being in compliance with this section. The phasing can be changed at the motor terminal box without requiring re-identification.

It appears the the CMP members have no understanding of how motors are installed in industrial occupancies. Almost always the terminations at the motor are completed before the motor circuit conductors are landed at the motor starter to avoid lockout issues. In my area, the motor termination will almost always be crimp terminals, screws and nuts, followed by rubber and vinyl tape. No matter what the code require may be, there is no way that we will make a rotation change at the motor terminal box.

 

[wwhitney]

If you want to change rotation at the motor starter, is it that much of a burden to retape the conductors at both the motor starter and at motor junction box? (I have no experience, so maybe retaping at the motor junction box would be trouble.) The 210.5(C)(1)(a) means of identification would then be "by tape if present, otherwise by insulation color."

Cheers, Wayne

 

[jap]

If you want to change rotation at the motor starter, is it that much of a burden to retape the conductors at both the motor starter and at motor junction box? (I have no experience, so maybe retaping at the motor junction box would be trouble.) The 210.5(C)(1)(a) means of identification would then be "by tape if present, otherwise by insulation color."

Cheers, Wayne

In a nutshell,,,, YES !!!!

The statement of problem and substantiation for public input is very well expressed.

Jap>

 

[jap]

From the feedback I received from some panel members, the IAEI saw the exception as a "serious" safety issue, and often the CMP will be swayed by the IAEI.
There is no safety issue. The only reason the identification by phase and voltage was put into the code was to help prevent the overloading of a the neutral of a multiwire circuit. My exception was clear that it only applied to branch circuits that supplied line to line loads.

NEMA submitted a similar proposal in the 2014 cycle.

It appears the the CMP members have no understanding of how motors are installed in industrial occupancies. Almost always the terminations at the motor are completed before the motor circuit conductors are landed at the motor starter to avoid lockout issues. In my area, the motor termination will almost always be crimp terminals, screws and nuts, followed by rubber and vinyl tape. No matter what the code require may be, there is no way that we will make a rotation change at the motor terminal box.

That's our process also.

I take back my previous misunderstanding.

Thanks for the clarification.

JAP>

 

[infinity]

It appears the the CMP members have no understanding of how motors are installed in industrial occupancies.

It extends beyond industrial. I stopped bothering with submitting PI's after reading some of their comments. They had no clue what was going on out there in the real world.

 

[don_resqcapt19]

If you want to change rotation at the motor starter, is it that much of a burden to retape the conductors at both the motor starter and at motor junction box? (I have no experience, so maybe retaping at the motor junction box would be trouble.) The 210.5(C)(1)(a) means of identification would then be "by tape if present, otherwise by insulation color."

Cheers, Wayne

That would assume that your directories specify tape as the means of identification. Most of the time they specify the insulation color as the means of identification. I guess you could specify both means, but you would have a labor increase by at least a factor of 10, to move the conductors at the starter and change the tape at both ends as compared to just ignoring the code and changing the rotation at the starter.

I doubt that anyone has ever actually complied with the rule as currently written, doubt they ever will.

 

[jap]

I worked in a plant where all the 480v conductors were black and all of the 120v conductors were red.
Saved a ton of wire, and, for this code requirement would result in nothing more than re-numbering or marking at the disconnect should you happen to have to swap the phases to change rotation.

JAP>