404.9 & 10 General-Use Snap Switches, Dimmers, and Control Switches.

Sections 404.9 and 404.10 now apply to control switches.
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Sections 404.9 and 404.10 now apply to control switches.

Code Change Summary: Revised code language now includes dimmers and control switches in the general requirements for snap switches.

In the past, NEC® Section 404.9 and 10 provided requirements for general-use snap switches and nothing more. In the 2020 NEC®, these sections now include dimmer switches and control switches.

These sections provide requirements such as:

Prior to the revised code language, it could be argued that a dimmer switch or control switch did not have to comply with the same rules as snap switches since dimmers and control switches were not specifically mentioned in these sections.  

Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.

2017 Code Language:

404.9 Provisions for General-Use Snap Switches.

404.10 Mounting of Snap Switches.

2020 Code Language:

404.9 General-Use Snap Switches, Dimmers, and Control Switches.

404.10 Mounting of General-Use Snap Switches, Dimmers, and Control Switches.

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404.9 & 10 General-Use Snap Switches, Dimmers, and Control Switches.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

Refer to the image of the control switch:

Which of the following is true?

A: The switch is rated for indoor use only.
B: The switch is rated for indoor or outdoor use.
C: The control switch in the image is not required to comply with 406.9 and 406.10.
D: The switch is not listed.
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