The electrical terms "line" and "load" refer to wires that deliver and carry power. Read on to learn more about line vs. load wiring.
TL;DR: “Line” refers to the wires bringing power into a device from the source; “load” refers to wires carrying power out to devices further down the circuit. Mixing them up on a GFCI outlet renders the protection useless. Knowing the difference prevents miswired devices, tripped breakers, and shock hazards.
The difference between the line and the load is that the line side connects between the power source and the incoming side of a device to provide it with power; the load side carries power from the device to other outlets or appliances downstream.
The terms line and load wires might sound technical, but they’re crucial to getting your circuits up and running safely. The line wire is where power flows into your device, while the load wire sends that power onward to whatever comes next.
The line side refers to the wiring carrying electricity from the source, while the load side refers to the part of the circuit that's delivering power to a certain load like a light, appliance, etc.
The Load wire is essentially a switched Line wire that carries power from a switch to the fixture or appliance it controls, energized only when the switch is “on.”
In this article, we will explain the difference between the LINE and LOAD terminals of a GFCI outlet, demonstrate the correct wiring method, and discuss the potential hazards and consequences of reversing the terminals (connecting LINE to LOAD and vice versa).
In electrical wiring, “line” refers to the incoming power and “load” refers to the outgoing power. The line side carries electricity from the source (your utility company or breaker panel) to a device, while the load side carries electricity from that device onward to the next one.