I only have the 2005 nec handy at the moment. If the stairway switches are going to control illumination for the stairway i think that pretty much implies that you have at minimum a 3 way switch arrangement controlling all stairway lights.
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Nec 3 way switch requirements. Page 1 of 2 does nec code require hardwired 3 way switches. It also applies to all occupancies not just residential. With this code change gone are the days of using dead end 3 way switches and 2 conductor switch loops. Ached garages with electric power. Were thinking of having some additional finishing work done on our basement and had the electrician in this am. This was a significant change in the nec that contractors and installers must be aware of to get right on the rough in as this applies to single pole three way and four way switches.
Posted in home automation. Your right i was reacting to the word required. One of the new lighting circuits will light a new hallway between the basement outside entrace down a wide hallway to a separate room. 21070 a 2 a at least one wall switch controlled lighting outlet shall be installed in hallways stairways attached garages and detached garages with electric power. A 3 wire nm connects the traveler terminals of the first and second 3 way switch together. Another switch location excused from the presence of a grounded conductor in the 2014 nec was a switch controlling a receptacle outlet as allowed by 21070a1 ex.
To do some planning and estimating. As no occupancy sensor will likely ever be listed for use with receptacle. I believe in 3way4way switching as neededdesired. While the current from an electronic lighting device on the egc is typically less than 050ma the installation of many electronic control devices at switch locations in a building can result in an accumulation of excess current on the egcs. Three way switches are required at each end of the hallway allowing the ceiling light to be turned on and off from both ends. The black line wire connects to the common terminal of the first 3 way switch.
If there are more doors served by a hallway such as for a bedroom or two you may want to add a four way switch near the door outside of each room. The only code i see regarding hallways says. You can use the white or gray conductor within a cable assembly for single pole three way or four way switch loops if it is permanently re identified to indicate its use as an ungrounded hot conductor at each location where the conductor is visible and accessible 2007c2. Typical 3 way switch wiring nm cable in the 1st diagram below a 2 wire nm cable supplies power from the panel to the first switch box. A grounded conductor installed at one of these switches would satisfy the requirements of 4042c.
Gallery of Nec 3 Way Switch Requirements
