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CE Code, Section 12 Wiring Methods

Posted By Steve Douglas, Sunday, March 01, 2009
Updated: Thursday, February 07, 2013

Between the 2006 and 2009 Canadian Electrical Code, Section 12 Wiring Methods has seen nine rule changes, and two appendix note changes. The intent of this article is to detail these changes along with rationale for the changes.

A new inserted Subrule 12-012(12)was added to read:Where underground raceways or cables are subject to movement by settlement or frost, provision shall be made so as to prevent damage to the conductors or the electrical equipment.This proposal was submitted by an IAEI inspector member from Ontario to address damage to installations during movement of the building, raceway or cable. This change also helps to harmonize requirements between the Canadian Electrical Code and theNational Electrical Code.

Subrules 12-106(4) and (5) were revised replacing ferrous and nonferrous with magnetic and nonmagnetic. The rationale given for this change was to recognize not all ferrous metals are magnetic and to make the requirements clearer for code users.

Subrule 12-108(4) was added to read:Where parallel conductors include grounded circuit conductors, each parallel set shall have a separate grounded circuit conductor.In addition the drawing in Appendix B was revised showing the location of grounded conductors. This proposal was generated by the Task Force on the Harmonization of Ampacities. This task force is sponsored by NFPA and CSA, and consists of members representing the Canadian Electrical Code Part I, National Electrical Code, Canadian Standards Association, National Fire Prevention Association, Underwriters Laboratories, International Association of Electrical Inspectors, Cable Manufacturers, Equipment Manufacturers, and Canadian Consumers.

Revised Drawings in Appendix B Rule 12-108

The Task Force on Harmonization of Ampacity identified the words at the bottom of the table in Appendix B for Rule 12-108, "Neutral may be located outside of the above groups in the most convenient location” leaves a questions for code users as to the meaning of the word "group”. The group should refer to a group of ABC conductors for three-phase, and a group of AB for single-phase.

Rule 12-112 was revised adding brazing as a method for conductor splicing. The Task Force on Harmonization of Ampacity identified the CE Code does not recognize installations where the conductors splicing using brazing or welding. As this practice has been shown in the U.S. to have no adverse effects on the ampacity capability of the conductors, the task force agreed to propose these revisions to Rule 12-112 allowing these installations.

Subrules 12-116 (1), (3) and (4) Termination of conductors was revised to read:(1) Connection of conductors to terminal parts shall be made by means of pressure connectors, solder lugs or splices to flexible leads, (3) Stranded and solid conductors No. 10 AWG and smaller shall be permitted to be connected by means of wire-binding screws, or studs and nuts that have upturned lugs or equivalent, and (4) Stranded and solid conductors larger than No. 10 AWG shall be terminated in solderless wire connectors or shall be permitted to be soldered into wire connectors specifically approved suitable for the purpose except where prohibited by Section 10.The reason for this proposal was to clarify termination requirements for the Code users (there was ongoing argument between the regulators and contractors in respect to the allowable number of conductors per a single terminal), to harmonize this requirement with Article 110.14(A) of theNEC, in light of work of the CANENA tri-national THC on wire connector standard, and to clarify that the connector intended for aluminum conductors must be specifically approved for the purpose and marked appropriately. This requirement is consistent with Rule 12-118(3) for electrical equipment and with Article 110.14(A) of the NEC for connectors.

Rule 12-608 was revised to read:Armoured cable shall be run in a manner such that the mechanical and electrical continuity of the armour is maintained throughout the run, and the armour of cables shall be mechanically and electrically secured to all equipment to which it is attached.The rationale given for this change was to clarify the language of the Code, to remove design and construction requirements from the existing rule and to remove inconsistency between the present wording and Rules 10-618 and 10-804.

Code users had expressed concerns the present requirement "the armour of cables shall be mechanically and electrically continuous throughout” of Rule 12-608 can not be met by installation, but it could be met only by the cable design and construction. These users indicated, armour of certain cables can not be "electrically continuous throughout”, and this is the reason that the armour is not allowed to be used as bonding means in accordance with Rules 10-618 and 10-804. It was indicated, if the armour is mandated to be electrically continuous by Rule 12-608, it should be allowed to be used as a bonding means by rules of Section 10. The proposed wording will clarify the language of Rule 12-608 and removes potential conflicts with other rules of the Code and with Part II standards.

The Appendix B note for Item 12-2200(a) was revised to read:The ideal support point for cable tray is at the one-quarter span point. Locating cable tray supports at or near the centre of a span or near cable tray joints may significantly increase the deflection of cable trays.The rationale for this proposal is to re-enforce the Appendix B note recommending the "ideal support point for cable be at the one-quarter span point.” Too often, installers place the support directly beneath a cable tray joint causing sagging and potential failure of the tray.

Items 12-2200(6)(c) and (d) were revised to read:(c) 600 mm horizontal clearance on one side of cable trays mounted adjacent to one another or to walls or other obstructions, where the width of the cable tray installation does not exceed 1 m, and (d) 600 mm horizontal clearance on each side of cable trays mounted adjacent to one another, where the width of the cable tray installation exceeds 1 m.The intent of this change is to ensure all parts of a cable tray can be readily accessed during and after construction.

NewSubrule 12-2200(7) was added to read:At least one expansion joint shall be installed in any cable tray run where the expansion of the cable tray due to the maximum probable temperature change during and after installation can damage the cable tray.The rationale for this change was to be constant with other wiring methods cover in the code.

Subrules 12-2210(1), (2) and (3) were revised adding the word "adjacent” to clarify that the spacing of conductors, cables, or both is based on the largest adjacent conductor. The rationale for this change was to address inconstant application of this rule. Some code users interpreted the previous rule to require the cable spacing on the largest cable in the cable tray, while others only looked at the effects of the adjacent cable.

In addition to the changes identified in this article,Section 12, along with other sections in the code, has numerous rules with the wordfixturesreplaced with luminaires.

Read more by Steve Douglas

Tags:  Featured  March-April 2009 

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