Article 404: Switches

Article 404 Switches

I. Installation




Switch Connections

Three- and four-way switches must be installed so that switching is in the ungroundedconductor. If the wiring is installed in metal raceways or metal-armored cable, it must be in accordance with the requirements of Section 300.20(A). A grounded conductor must not be switched. There are two exceptions.



Switches or circuit breakers must be externally operable and mounted in an enclosure that is listed for the use intended. There are two exceptions. The enclosure cannot be used as a junction box, auxiliary gutter, or a raceway for conductors going through or tapping off to other switches unless complying with 312.8.


Wet Locations

If used in a wet location or outside, the switch must be placed in a weatherproof enclosure or cabinet and comply with 312.2(A). If it is used in a tub or a shower it must be part of a listed tub or shower assembly.


Time Switches, Flashers, and Similar Devices


Position and Connection of Switches

(A) Single-Throw Knife Switches. They must be placed so that gravity will not tend to close them. If they are approved for an inverted position, then there must be a lock so that the blades remain open after being opened.

(B) Double-Throw Knife Switches. They can be mounted either vertically or horizontally. If vertical then there has to be a means to hold the blades open when they are set.

(C) Connection of Switches. Basically the switches have to be connected so that the terminals supplying the load are de-energized when the switch is open. Single-throw knife switches and switches with butt contacts must be connected so that the blades are de-energized when the switch is in the open position.



Usually switches are mounted so that the on position occurs when the switch is up when vertically mounted. There are two exceptions.


Accessibility and Grouping

(A) Location. They must be located so that the grip of the operating handle is not more than 2.0 m (6 ft. 7 in.) above the floor or platform.

(B) Voltage between Adjacent Devices. The voltage between adjacent ganged switches cannot be more than 300 unless there are permanent barriers between the switches.


Provisions for General-Use Snap Switches

(A) Faceplates. The faceplate must completely cover the opening for the box or enclosure. If the switch is flush mounted the faceplate must sit flush against the finished surface that the switch is mounted on.

(B) Grounding. The switches and dimmers must be grounded, and the metal faceplate must be grounded. This can be done two ways. One is by connecting an equipment grounding conductor or bonding jumper to the grounding termination on the snap switch. The other means is that the switch is installed with metal screws that make direct contact with the metal box unless the switch is the self-grounding type or mounted on a nonmetallic box with a means for grounding. There is an exception where there is no grounding means and it is a replacement.



Mounting of Snap Switches


Circuit Breakers as Switches


Grounding of Enclosure


Knife Switches


Rating and Use of Snap Switches

There are ratings discussed for alternating-current general-use snap switches, alternating-current or direct-current general-use snap switches, CO/ALR snap switches, alternating-current specific-use snap switches rated for 347 volts, and dimmer switches.

II. Construction Specifications



They must be marked with current, voltage, and the maximum horsepower if horsepower rated.


600-Volt Knife Switches


Fused Switches

Parallel fusing is not permitted except as noted in Section 240.8.


Wire Bending Space

Article 90 Introduction


Wiring and Protection

Wiring Methods and Materials

Equipment for General Use

Special Occupancies

Special Equipment

Special Conditions


Annex C. Conduit and Tubing Fill Tables for Conductors and Fixture Wires of the Same Size

Annex D. Examples

Annex E. Types of Construction

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Pocket Guide to the National Electrical Code 2005
Pocket Guide to the National Electrical Code(R), 2005 Edition (8th Edition)
ISBN: 0131480014
EAN: 2147483647
Year: 2004
Pages: 120 © 2008-2017.
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