Guide to the Canadian Electrical Code, Part I — Instalment 28

September 6, 2017

By William (Bill) Burr

In this article: Section 56 — Optical fibre cables. Section 56 is a supplementary or amendatory section of the code and applies to the installation of optical fibre cables in conjunction with all other electrical systems. Rule 56-002 provides a special terminology definition for an Optical Fibre Cable — a cable consisting of one or more optical fibres that transmits modulated light for the purpose of control, signalling or communications.

Rule 56-102 outlines that there are three types of optical fibre cables:

• non-conductive cables containing no metal other conductive materials
• conductive cables containing non-current carrying conductive material such as strength member, metal vapour barriers or metal sheaths or shields
• hybrid cables that contain both fibre optic and current carrying electrical conductors

The CE Code Handbook contains diagrams showing the construction of each type.

Rule 56-104 requires that optical fibre cables installed, within buildings, be approved types as listed in Table 19 and where installed outdoors be suitable for the location with respect to moisture, corrosive atmosphere, temperature, degree of enclosure and exposure to mechanical damage. Also note that OFNP, OFNR, OFNG, OFN, OFNH, OFCP, OFCR, OFCG, OFC, and OFCH have a minimum cable temperature rating of 60°C. Where a cable is used in a greater temperature, the rating must be marked on the cable.

Rule 56-106 states that, as per paragraph (a) in the Scope of the code, optical fibre installations by an electric power or communications utility, in its function as a utility, are not subject to inspection and acceptance by an inspector.

Rule 56-200 prohibits non-conductive optical fibre cables from occupying the same raceway, cabinet, panel, outlet box or similar enclosure with conductors of electric light, power or Class I circuits, unless they are functionally associated and the number and size of conductors meet applicable requirements of the wiring method. There is an exception for industrial establishments, where authorized persons supervise and maintain the installation.

Rule 56-202 permits conductive optical fibre cables to occupy the same raceway with conductors of a Class 2, communication or community antenna distribution and radio television circuits in accordance with Sections 16, 54, and 60. However, this rule prohibits conductive optical fibre cables occupying the same raceway, panel, cabinet or similar enclosure with electric light, power or Class I circuits.

Sub-clause (3) of this rule prohibits conductive optical fibre cables occupying the same cabinet, panel, outlet box, or similar enclosure housing the electrical terminals of a Class 2, communications, community antenna distribution, or radio and television circuit except where they are functionally associated or factory assembled in the enclosure. In accordance with Section 10, all conductive non-current carrying parts of conductive optical cables must be bonded to ground.

Rule 56-204 permits optical fibre cables to be incorporated in hybrid cables with electric light, power, or Class I circuits not exceeding 750 volts, or Class 2, communications, community antenna, or radio and television circuit conductors with associated functions. In every case, the hybrid cable is classed as per the type of electrical circuit conductors in the cable and installed according to the rules for that type.

Rule 56-206 requires that where an optical fibre cable penetrates through a fire separation it shall be installed in accordance with Rule 2-128 to prevent fire spread.

Rule 56-208 requires optical fibre cables installed in a vertical shaft to be totally enclosed in non-combustible raceway unless they meet the flame spread requirements of the National Building Code of Canada or local building legislation for buildings of non-combustible construction (FT4). This requirement applies to hybrid cables, as well.

Rule 56-210 provides that optical fibre cables not be installed in ducts or plenum chambers unless they meet the flame spread requirements of the National Building Code of Canada or local building legislation and the provision of Rule 12-010 – Wiring in ducts and plenum chambers

Rule 56-212 requires that all raceways containing optical fibre cables must be installed in accordance with Section 12.

Rule 56-214 requires that where conductive optical fibre cables are exposed to lightning or accidental contact with electric light or power cables the metal parts must be bonded to ground at the point, as close as possible, to the point the cable enters the building.

In the next instalment, we will be discussing Section 58 — Passenger ropeways and similar equipment.

* The source for this series of articles is the Canadian Electrical Code, Part I, published by CSA

** Note the CEC Handbook is also published by CSA.

William (Bill) Burr is the former Chair of the Canadian Advisory Council on Electrical Safety (CACES), former Director of Electrical and Elevator Safety for the Province of BC, and former Director of Electrical and Gas Standards Development and former Director of Conformity Assessment at CSA Group. Bill can be reached at Burr and Associates Consulting billburr@gmail.com.