Article 300.3 of 1999 NEC

[Michael Park]

I am an Electrical contractor in Northern Virginia that needs an opinion from your forum. I have an authority that is saying that an installation is not conforming to NEC 300.3. This is the scenario. We have installed several long runs of 3/4" rigid conduit through a tunnel system. At each location of a lighting fixture or wiring device we installed a T condulet for wiring access to the fixture or device. In theses runs there are three (3) individual circuits originating from the same source sharing a neutral (grounded conductor)and ground. At the condulet, we have taken the designated phase conductor, grounded conductor, and grounding conductor out to the fixture/device and back to the condulet to continue it on to the next device/fixture. The other two phase conductors continue through the condulets until they are dropped as designated. This was done to eliminate the need for a splice in the condulet and to eliminate a potential maintenance point for the owner/maintainer. The authority has issued an opinion that this type of installation violates article 300.3. We contend that article 300.3 addresses conductors of the same circuit, and not multiphase circuits, and that if applied to the other phase conductors passing through the condulets that they are still contained in the same raceway. The authority is aying that by Article 300.3 we would have to take the other two phase conductors in and out of the device/ fixture at each location or provide a splice in the condulet. What is the opinion of the forum on this situation? Do you feel taht this is a violation of article 300.3? Thank You

 

[augie47]

Re: Article 300.3 of 1999 NEC

opinion from one inspector:
I would have no problem with what you described.

 

[infinity]

Re: Article 300.3 of 1999 NEC

I don't see why their installation would be any better than yours. If the condulet were a junction box and you spliced the 3 conductors feeding the fixture the other two circuits would still be pulled straight through the box. I don't see any logical reason to bring the additional circuit conductors in and out of the fixtures. Your installation is a very common one when using T condulets. I don't see how 300-3 would apply.

 

[don_resqcapt19]

Re: Article 300.3 of 1999 NEC

The code permits multiwire circuts to be considered as multiple circuits. [210.4(A)] If you consider your multiwire branch circuit as three circuits, then 300.3(B) is complied with.
Don

 

[jim1]

Re: Article 300.3 of 1999 NEC

Mike
I am adding to your question, the wiring from your T-to the device is approx. 15 feet. The authority has stated that the question should be:
does 300.3/300.5 allow you to run 1-circuit conductor/2 bonding conductors and 2 neutral conductors in the same conduit. He states that the second neutral conductor in the conduit has no means to cancel out any current it may be carrying, creating a possible unbalanced condition which results in heat and would increase the overall circuit impedance (in theory) .
The neutral conductor is the same wire in and spliced in the device box going back up the same conduit. ??????

 

[Michael Park]

Re: Article 300.3 of 1999 NEC

In response to the question of increased impedance, this would only apply if the second set of neutral conductors were in a separate raceway. Since they are in the same conduit in and out, it is my contention that there is no possibility of any unbalanced load occurring. If for some reason two conduits were run into the device/fixture,with the phase conductor, neutral and grounding one, and then only the neutral and ground left to return to the original run in the other conduit, then this condition could occur. This was not the installation so the conditions of 300.3, and 300.5 do not apply. If anyone else has an opinion, please post a reply.