Q: There has been a lot of discussion about wiring receptacles with pigtails instead of making the connections at the receptacle itself. But what about switches, especially three-way switches? Is there any advantage (or requirement) to wiring those with pigtails?
A: David Herres, a licensed electrician in Clarksville, N.H., responds: It is correct that the National Electrical Code, which has jurisdiction in such matters, states that receptacles are to be wired using separate pigtails tapped from the branch circuit that feeds downstream devices. The purpose of this requirement is to ensure that ground continuity is maintained throughout the branch circuit when a device is removed even temporarily. Ground continuity is an issue for the neutral (white) conductor and for the equipment-grounding (green or bare) conductor.
With switches, however, maintaining neutral continuity is not a concern. When properly installed switches are placed in series with the load or loads in the ungrounded (usually black or red) conductor, the grounded conductor is not interrupted when the switch is removed. The line from the switch connects straight through to the next enclosure—for example, a ceiling fixture. With regard to the equipment-grounding conductor, it is necessary to take a good, hard look at the installation and make sure that a hazardous situation is not created if this line is interrupted.
As far as three-way and four-way switches are concerned, the situation is the same. Think of a pair of three-way switches in conjunction with any number of four-way switches as a “black box” that is equivalent to one single-pole switch. They are placed in the ungrounded (hot) line, and there is no need to hook them up with pigtails because, again, the neutral is not interrupted. But always make sure that the equipment-grounding conductor retains continuity.
