The load is the wire going out to the third device on the circuit and so on. In some cases line wires are marked with line pwr or a lightning bolt symbol.
Electrical Switches Electrical 101
Line vs load light switch. With the switch turned off you should see 120v on the line wire when testing to ground and 0v on the load wire when testing to ground. If a switch is connected to the neutral side of a light bulb or other load the bulb will always be connected to the line even when the switch is turned off. The two wires that connect between the 3 ways switches are carriers. If the line side is the side with the power coming in then the load side would be the side with the power going out. When referring to an electric device that can be connected to another one such as a receptacle line refers to the wires feeding it from the panel which is upstream from the device in terms of the flow of electricity. With the first device the line is the wire running from the service panel to the device and the load is the wire running from the first device to the second device downstream on the circuit.
Not sure about connecting it backwards just use a meter to make sure you know which line coming into the box is 120v and you wont have any problems. A second meaning for load is the magnitude of the energy consumed by the devices on the circuit. An electrical load is an electrical component or portion of a circuit that consumes electricity. A switch must be connected to the line side of a load and not the neutral. On the other hand load refers to devices on the same circuit that are downstream of the one in question. Remember that one side of the common on the three way is the line side and the other common is the load side or switch leg.
If the wire is coming from the top of the switch box it is likely your load wire. Load wire generally connected to the top half of your switch. Line wire generally connected to the bottom half of your switch. The load line is connected to the device power lead. The circuit path is open and no current flows through a circuit. Sounds like you have it right.
Use a meter to determine which this is. The switch line should be connected to the hot line in the jbox. When you addressing two 3 ways and one 4 way. If you have a 4 way it simply flips the carriers two carriers in two carriers out. At the second device the line is the power source coming in from the first device. Ground is not shown in the diagrams below.
If youre not sure what a load is then let me explain. You may not have had a good contact point when testing or way worse youve got an outlet or switch that is grounding out reducing the potential between your line and ground.
Gallery of Line Vs Load Light Switch
