Can I Run Parallel Service Conductors In The Same Conduit

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In the 2017 NEC, parallel conductors inside an auxiliary gutter must exist grouped together to preclude current imbalance in the paralleled conductors due to inductive reactance.

Code Change Summary: A new code section provides requirements for parallel conductors in an auxiliary gutter.

Parallel conductor installations are covered in NEC 310.x(H) and are permitted for each phase, polarity, neutral, or grounded conductor in sizes 1/0 AWG and larger. Joining conductors in parallel is like having two or more smaller conductors continued at each end to brand ane larger usher. This is often done to make wire pulling easier.

In order to install conductors in parallel, the paralleled conductors in each phase, polarity, neutral, grounded excursion conductor, equipment grounding usher, or equipment bonding jumper must comply with all of the following:

(1) Be the same length.

(2) Consist of the same conductor textile.

(3) Be the same size in circular mil surface area.

(4) Take the aforementioned insulation type.

(5) Be terminated in the same manner.

The in a higher place rules ensure that each set of parallel conductors carries the same ampacity. Where run in separate cables or raceways, the cables or raceways must have the same number of conductors and must take the same "electrical characteristics".

The phrase "electric characteristics" refers to the properties of the raceway such every bit raceway material. Using the same raceway blazon (nonmetallic or ferrous metal) for each parallel set of conductors ensures that electrical electric current is non transferred to the raceway through induction.

In the 2017 NEC, additional code language was added to address proper grouping of parallel conductors inside an auxiliary gutter. Earlier the lawmaking change, the requirements for grouping of the parallel conductors was express to within each raceway or cable merely no mention was made well-nigh what goes on inside the gutter box.

Department 300.twenty(A) states the post-obit: Where conductors conveying alternating current are installed in ferrous metal enclosures or ferrous metallic raceways, they shall be arranged then as to avoid heating the surrounding ferrous metal by consecration. To accomplish this, all phase conductors and, where used, the grounded usher and all equipment grounding conductors shall exist grouped together.

Most auxiliary gutters are fabricated of ferrous metal therefore it simply makes sense to keep parallel conductors grouped properly behind the gutter box encompass.

A similar lawmaking change occurred in Article 376 for metal wireways.

Below is a preview of Article 366. Come across the bodily NEC text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC edition of NFPA lxx.

Source: https://www.electricallicenserenewal.com/Electrical-Continuing-Education-Courses/NEC-Content.php?sectionID=297.0#:~:text=Parallel%20conductor%20installations%20are%20covered,to%20make%20one%20larger%20conductor.

Posted by: morriscouttepore1968.blogspot.com

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