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General use snap (light) switch bonding – Code File May 2020

May 9, 2020 | By Tatjana Dinic

May 9, 2020 – Questions have been asked if a general-purpose snap (light) switch that includes a bonding terminal is permitted to be bonded to an outlet box without a bonding conductor.

CE Code Rule 10-612 3) requires a bonding connection to be made at every non-metallic outlet box for any device that requires connection to a bonding conductor. For any device that has a bonding terminal and is installed on a metallic outlet box, Rule 10-612 5) requires a bonding conductor to be installed to bond the device to the enclosure.

Subrule 5) is a change in CE Code 2018 with the re-write of Section 10. Since the previous CE Code (2015 ed.) had specific requirements for bonding jumper for receptacles only, this change raised some questions regarding light switch bonding.

A recently approved amendment to Rule 10-612 for the upcoming 2021 CE Code will clarify that some devices—such as a general use snap (light) switches—will not require a bonding conductor to the outlet box. Manufacturers confirm that a general use snap switch, certified to CSA C22. 2 No. 111, can be bonded to a metallic or non-metallic outlet box via the mounting screw or yoke. Based on standards testing, metallic and non-metallic outlet boxes are required to provide a bonding connection at the mounting screw termination point.


A new Appendix B Note to Rule 10-612 3) has been approved, and will appear in CE Code 2021 (typically published by CSA in January, and effective in Ontario by 2022) as follows:

CSA C22.2 No. 42 General use receptacles, attachment plugs and similar wiring devices, requires that receptacles be connected directly to a bonding conductor. For some other devices, such as switches, the bonding connection is permitted to be made via the mounting screws to the device enclosure. CSA C22.2 No. 18.2 Non-metallic Outlet Boxes requires that the mounting screw termination point of a device enclosure be electrically connected to a bonding means within the non-metallic device enclosure. Installers should consult the manufacturer instructions for proper installation of wiring devices.

Therefore, for general use snap switches that include a bonding terminal, a bonding conductor is not required to satisfy Rule 10-612. The screws and the yoke mounting the switch to the outlet box enclosure also meets requirements of Rule 10-612 based on certification requirements.

Always consult your AHJ for more specific interpretations.

About the author…

Tatjana Dinic, P.Eng., is the acting director for Engineering & Program Development at Ontario’s Electrical Safety Authority (ESA) where she is responsible for product safety, code development, improving harmonization and alternative compliance, and aging infrastructure programs. She is a Professional Engineer with an M.Eng. degree from University of Toronto and a member of CE Code-Part I, Sections 4, 10 and 30. Tatjana can be reached at tatjana.dinic@electricalsafety.on.ca.

This article—along with other great content—appears in the May 2020 edition of Electrical Business Magazine.

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