Lights switched from two different locations are called three-way switches. When lights are switched from three or more locations, they
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A: 1/2 switched outlet. Both hot and neutral pre-scored conduction tabs must be snapped off when the upper and lower outlets are supplied by separate breakers.
B: Ganging Neutrals. This wiring configuration is wrong and will create net current and magnetic fields.
C:This diagram shows the correct configuration, which will not generate magnetic fields.
2 fomex
1 hot"
I neutral J ground
Properly wired З-way switch.
are called four-way switches. A correctly wired three — or four-way switch will not emit magnetic fields. However, these switches are often wired incorrectly and thus become a source of magnetic fields that can radiate throughout the room. To avoid improperly wired three — or four-way switches, specify the following:
• Three-wire Romex shall be used between the switches when wiring a three-way switch (see illustration). If alternate wire is used, it shall be twisted.
• Each three — or four-way switch must be controlled by a single breaker.
• All wiring for three — or four-way switches shall be contained in a single run of wire or a single metal conduit. All runs not in a conduit must be bundled.
Dimmer switches are a source of magnetic and radio frequency fields. If these switches are used, they should be located at a distance from seating and sleeping areas. The most expensive name-brand dimmers tend to emit smaller fields. Choose a model that emits no fields when all the way on or all the way off.
