Disecting article 300.5(I) of the NEC

[jim dungar]

All of the examples in Annex B, show isolated conductors or they show all conductors. Maybe Neher and McGrath need to be examined?

 

[mwm1752]

Commentary after 300.5(I) ex 2 'Isolated phase installations contain only one phase per raceway or cable." does give some value to the term isolated. In referencing 300.3(B)(3) I do not see where 300.20(B) (only refers to single conductors in metal piping) or 332.31 ( which refers to if single conductors are used they shall all be grouped) draws the assumption to split & group phasing as discuused. IMO it seems to deter the install as such.

 

[roger]

Commentary after 300.5(I) ex 2 'Isolated phase installations contain only one phase per raceway or cable." does give some value to the term isolated. In referencing 300.3(B)(3) I do not see where 300.20(B) (only refers to single conductors in metal piping) or 332.31 ( which refers to if single conductors are used they shall all be grouped) draws the assumption to split & group phasing as discuused. IMO it seems to deter the install as such.

Remember, the hanbook commentary is just another opinion and even with that being the case, the writers have simply not addressed the issue at hand.

What I want to see is if someone has a reason electrically that the installation shouldn't be allowed.

Roger

 

[mwm1752]

I've been submitting code that directs the install to be single conductor or grouped circuit install. You have the right to disagree but I have not seen a response from you per code that verifies your responses. Maybe you should submit the detailed electrical theory that there is no possible harm that could come from the install proposed.

 

[roger]

I've been submitting code that directs the install to be single conductor or grouped circuit install.

It seems to me that you've been substantiating your stance based on handbook commentary, not code.

You have the right to disagree but I have not seen a response from you per code that verifies your responses. Maybe you should submit the detailed electrical theory that there is no possible harm that could come from the install proposed.

Simply stated, If theses conductors (regardless of how they are grouped) are installed in close proximity to each other in plastic raceways, currents and EMF will be negated the same as if they were in an open trench so there is no issue, do you disagree with that?

Roger

 

[don_resqcapt19]

Commentary after 300.5(I) ex 2 'Isolated phase installations contain only one phase per raceway or cable." does give some value to the term isolated. In referencing 300.3(B)(3) I do not see where 300.20(B) (only refers to single conductors in metal piping) or 332.31 ( which refers to if single conductors are used they shall all be grouped) draws the assumption to split & group phasing as discuused. IMO it seems to deter the install as such.

I am not really sure what you said, but in my opinion 300.3(B)(3) permits any combination of conductors to be run in non-ferrous raceways without being grouped. 300.20(B) just applies where the ungrouped raceways or cables enter a ferrous enclosure.

 

[mwm1752]

Where does 300.3(B)(3) refer to splitting up conductors of a single branch circuit into multiple raceways as the OP states. The other sections 300.20(B), 332.31 are in which the conductors shall comply with the provisions. 300.3(B) is the charging statement 1 thru 4 are not exceptions but addition to the charging statement IMHO

 

[iwire]

Every comment with exception to one has been from the code. Please reread to understand. I have read your code & decipered the values. Have you mismanaged a project & looking for an out? If you can't format a valid case through theory as requested our conversation will cease.

Wow, you are kind of full of yourself. :roll:

When I read exception 2 to code section 300.5(I) I see it can be interpreted in more than one way.

Do you see that?

When I see a code section that can be interpreted in more than one way I try to use common sense in deciding which way to go.

Now considering there is no electrical safety reason to prohibit a AB / CN installation I choose to interpret exception 2 as allowing it.

 

[roger]

If you can't format a valid case through theory as requested our conversation will cease.

Okay but, I would appreciate an answer to my question in post #25


Roger

 

[don_resqcapt19]

Where does 300.3(B)(3) refer to splitting up conductors of a single branch circuit into multiple raceways as the OP states. The other sections 300.20(B), 332.31 are in which the conductors shall comply with the provisions. 300.3(B) is the charging statement 1 thru 4 are not exceptions but addition to the charging statement IMHO

How are they not exceptions?...yes not worded as such, but only because of the NFPAs push for "positive" code language.

300.3(B) ...unless otherwise permitted in accordance with 300.3(B)(1) through (B)(4).

300.3(B)(3) says that when you have nonferrous wiring methods, that the "charging statement" in 300.3(B) does not apply.

 

[jusme123]

The use of 300.3(B)(1) has to be based on the definition of "isolated phase". That is not a code defined term. I can easily see the AHJ as requiring only one phase in a raceway when that rule is used. I don't know if that is the intent or not. Again, I just bypass that rule and go to 300.3(B)(3).

Don, IMO you can just bypass a code rule that deals directly with your install, which limits the install to isolated phases, as listed in art 300.3(B)(1) (exc.), which deals with parallel conductors installed underground in PVC. Also, 300.3(B)(3) does not deal with parallel ckts as 300.3(B)(1) does.

300.3(B)(1)(exc) limits the install, it is also repeated in the NEC in art 300.5(I)(exc#2), which proves the NEC's intent with respect to parallel conductors installed underground in PVC.

 

[jusme123]

It seems to me that you've been substantiating your stance based on handbook commentary, not code. Simply stated, If theses conductors (regardless of how they are grouped) are installed in close proximity to each other in plastic raceways, currents and EMF will be negated the same as if they were in an open trench so there is no issue, do you disagree with that?

Roger

The continuity of art. 300.3(B)(1)(Exception) and art. 300.5(I)(Exception#2) makes it clear how the NEC wants paralleled conductors, in underground PVC, installed. If all circuit conductors are not installed within the same raceway, the NEC allows you to install isolated phases in each conduit. IMO, adding the issue of open trench clouds the discussion because they are not run in open trench, and the exceptions listed above deal exclusively with the installed PVC.

"shall be permitted to be arranged as isolated phase installations" IMO the code is clear, if phases AB are in the same conduit, it is not an isolated phase installation.

 

[iwire]

Don, IMO you can just bypass a code rule that deals directly with your install,

I have to agree with you on that point.

"shall be permitted to be arranged as isolated phase installations" IMO the code is clear, if phases AB are in the same conduit, it is not an isolated phase installation.

A&B in one C&N in another. Is A isolated from C, is B isolated from N? Yes.

That being the case phases are isolated, again I see nothing in exception 2 that demands all phases be isolated and there is no safety reason to require that.

 

[don_resqcapt19]

... Also, 300.3(B)(3) does not deal with parallel ckts as 300.3(B)(1) does. ....

Where does the code state that 300.3(B)(3) does not apply to parallel circuits? Just because (B)(1) exists, it does not mean that (B)(3) cannot apply to parallel circuits.

As far as the code intent goes, it is clear, based on the two sections in question, that the CMP really does not know the intent of the section. As our discussion show, they can be read as being in conflict with each other.

 

[jusme123]

Where does the code state that 300.3(B)(3) does not apply to parallel circuits? Just because (B)(1) exists, it does not mean that (B)(3) cannot apply to parallel circuits.

As far as the code intent goes, it is clear, based on the two sections in question, that the CMP really does not know the intent of the section. As our discussion show, they can be read as being in conflict with each other.

don, imo, the two sections in question show continuity when applied as stated, they both state that parallel conductors installed in pvc underground can be installed as isolated phase installations.

You seem to think the intent is not known only because you want to skip over applicable sections.

 

[jusme123]

I have to agree with you on that point.




A&B in one C&N in another. Is A isolated from C, is B isolated from N? Yes.

That being the case phases are isolated, again I see nothing in exception 2 that demands all phases be isolated and there is no safety reason to require that.

... "shall be permitted to be arranged as isolated phase installations" , which imo means each phase, not a group of phases or one particular phase. IMO the code gives you two choices, either group each set (ABCN)(ABCN)of parallel circuit conductors in each conduit, or install them as isolated phase installations (AA)(BB)(CC)(NN)

 

[don_resqcapt19]

don, imo, the two sections in question show continuity when applied as stated, they both state that parallel conductors installed in pvc underground can be installed as isolated phase installations.

You seem to think the intent is not known only because you want to skip over applicable sections.

CMP 3 had an opportunity to tell me that 300.3(B)(3) does not apply to parallel systems in a panel statement on a comment I submitted, but they stopped short of doing that.

3-4 Log #2254 NEC-P03 Final Action: Reject
(300.3(B)(1) Exception)
____________________________________________________________
Submitter: Donald A. Ganiere, Ottawa, IL
Comment on Proposal No: 3-11
Recommendation: The proposal should be accepted.
Substantiation: The panel rejected this proposal with the statement that isolated phase installations would not be permitted if the exception to
300.3(B)(1) were to be deleted. I disagree. The exception is not needed as isolated phase installations are permitted by the wording in 300.3(B)(3). The exception adds nothing to the understanding of the code.
Panel Meeting Action: Reject
Panel Statement: Section 300.3(B)(1) Exception must remain in the NEC as a very specific application where paralleled conductors are installed in
an underground installation with special permission to install isolated phase installations (all of one phase) in a nonmetallic conduit. These underground duct banks are installed in this manner to permit easy installation of these
paralleled conductors on cable racks in a concrete manhole. Without this exception, some AHJs might have problems with acceptance of this type of installation. Leaving it in the NEC provides clear direction on this application.
Number Eligible to Vote: 13
Ballot Results: Affirmative: 13
___________________________

The panel statement very strongly suggest that 300.3(B)(3) would permit what 300.3(B)(1) specifically permits, but the panel's opinion was that the AHJs might not understand that.

Note that the panel statement also says that the intent of 300.3(B)(1) is that each raceway contain only one phase.

 

[jusme123]

CMP 3 had an opportunity to tell me that 300.3(B)(3) does not apply to parallel systems in a panel statement on a comment I submitted, but they stopped short of doing that.

The panel statement very strongly suggest that 300.3(B)(3) would permit what 300.3(B)(1) specifically permits, but the panel's opinion was that the AHJs might not understand that.

Note that the panel statement also says that the intent of 300.3(B)(1) is that each raceway contain only one phase.

nice find, Don!! It also shows that 300.3(B)(1) is the applicable code for parallel installs, underground in pvc

 

[don_resqcapt19]

nice find, Don!! It also shows that 300.3(B)(1) is the applicable code for parallel installs, underground in pvc

It also tells me that CMP3 says that 300.3(B)(3) would permit the same installation, but without the "isolated phase" restriction.

 

[iwire]

... "shall be permitted to be arranged as isolated phase installations" , which imo means each phase, not a group of phases or one particular phase.

You are choosing to read it that way, it does not say that.