What is a Carter 3-way?
What is a Carter 3-way?
The Carter system was a method of wiring three-way switches in the era of early knob-and-tube wiring. This now-obsolete wiring method has been prohibited by the USA National Electrical Code since 1923, even in new knob-and-tube installations which are still permitted under certain circumstances.
What is Carter system?
A Carter system is an old style method used with knob and tube wiring. The hot and neutral are the travellers and the load is the common. Basically you are switching the polarity of the socket itself.
At what terminal of 3-way switch we connect wire going to the load?
The common terminal is the “bridge” between the power supply and the load (typically a light fixture). With this in mind, the wire that attaches to the common terminal is either (1) a hot wire from the main board or (2) leads to the load (fixture).
Why is it called a 3 way switch?
They are called 3 way switches. The reason is that there are 3 different states for the circuit. Each switch has 2 possible circuits for the hot wire to pass through. If both switches agree on one circuit for the hot wire, then they pass the current through and the light turns on.
How many switches can be on a 3 way?
two switches
3-way switches are used to control lights with two switches. These switches do not have an on/off position like single pole switches.
Where does the neutral wire go on a 3-way switch?
The other wires in a circuit with 3-way switches are the neutral (usually white) and ground (usually bare copper or green). The neutral wire bypasses both 3-way switches but connects to the light fixture. The ground connects to the ground terminal on each switch and to the light fixture.
Why is a 3-way switch called 3-way?
Circuits controlled by two (single pole, double throw) switches are called three-way by convention to distinguish them from circuits controlled by one (single pole, single throw) switch, which may be considered two-way (on, off). Clearly, three-way switches also arguably have only two functional states (on, off).
How many switches can be on a 3-way?
When should you use a 3-way switch?
Three-way switches are commonly used to control a light fixture from two different locations. For example, a long hallway or stairway might use a pair of three-way switches at each end so that lights can be turned on when approaching one end of the hall or stairway, then shut off from the other end.
