Q&A for How to Wire a Contactor

There are all different kinds of contactors out there, and they're all wired differently. Consult the diagram that came with your contactor and follow their instructions.

Most conductors label the terminals with letters like L, N, E, A1, A2, L, and P. Those correspond with the letters on the diagram that came with your contactor. It should make it a lot easier to wire everything together.

A loop is a fastener consisting of a ring that protects the inside surface of a small hole.

A contactor is basically just a switch. A programmable logic circuit (PLC) usually consists of many electrical components controlled by a computer program, one of which is frequently a contactor.

A contactor operates in a similar way to a relay. The contactor contains a coil which, when energized, "pulls in" the contacts, which will send output voltage to the desired device.

I had to do this a few times with floodlights to be used outside. Break your circuit, L N E through your contactor. Link a permanent live and a neutral from your supply to your coil (Al + A2) then use your switch feed to your photocell from A1, and switch the wire to the switched phase of your contactor load. This should now open when light, close when dark.

It takes two wires, one neutral and one switched wire for control of the contractor. The switched wire can be controlled via a switch, controller or pilot relay.

Wiring should be done when power is off. Identify the manufacturer's info on the two input pins and the output contact, Use a cable stripper to avoid jutting wires during connections, After identifying the input and output terminals, start the connections. Ensure that all wiring is fully tight.

The lights connect to the output ports on the contactor. The contactor will have space for the red power wires coming in from the photocell, circuit breaker, and lights. The black power wires will need to be tied together externally, such as through a wire nut.

Amps represent the amount of power in an electrical current. Volts means the force pushing the current through the circuit. Think of it like a water pipe. The amps would be the amount of water, while volts would be the water pressure.

Check the voltage and amperage of the device you want to control and the voltage for the control coil, then match it to the contactor.