Over time, electricians and other trades adopted various standard phrases and words to aid them in their work. These words or phrases are often oblique in meaning unless you fully understand the work involved. The words Line and Load are often used by electricians to identify specific terminals on a device and specify how those terminals should be wired. Does this Spark an idea?
Terminals
The terminals on electrical devices are often labeled so that electricians can identify them and will understand wire them. Wiring a device incorrectly will usually result in the device not working properly, not working at all, tripping a circuit breaker or damaging the device. Always identify the device terminals by color and marking before connecting any wires.
Wires
The wires that connect a device to the power supply, such as the wiring in a house, must be able to carry the amount of current the device is rated for. National electrical code requires that the wiring between a circuit breaker and the devices it serves be capable of handling the current rating of the circuit breaker. Other codes specify the wire colors, the insulation types and sometimes the type of circuit breaker or fuse that must be used with a specific type of device.
Line
The line terminals of a device connect to the power supply wires which connect to the circuit breaker or fuse. Line in this case means supply. The line wires are Hot wires. They may usually be any color but green or bare copper. If sheathed cable such as Romex is used, the wires will be black and white and sometimes include a red wire. Line terminals identified by color require the white wire to connect to the silver terminal and the black or red wire to connect to the gold or brass terminal.
Load
The load terminals connect a device to something that uses electrical power like a motor, air conditioning unit, furnace or electric heater. The Load is the device that uses the electrical power. The terminals may be different colors or the same color, depending on the type of power the device is supplying.
Example
Wiring for a central air conditioning unit located outside a home must include a fused cutoff switch located within reach of the unit. Two hot wires run from the cutoff switch line terminals to the double pole circuit breaker in the circuit panel inside the house. A pair of heavy duty fuses connects the load terminals to the line terminals. Two wires run from the line terminals to the air conditioning unit itself. The cutoff switch functions as a the device within the circuit to control the air conditioning unit and uses both line and load terminals.
Tags: circuit breaker, conditioning unit, line terminals, cutoff switch, load terminals, breaker fuse
