The Parts of an Electrical Control Wire

• Control wires come in many different shapes and forms. B2M Productions/Polka Dot/Getty Images

  Many systems rely on control wiring. Control wires are different than power wires, in that a continuous source of electricity does not flow through them. Control wires, rather, carry a signal only when a sensor sends out or receives electricity. Airplanes, robots and even home appliances all have control wires. All control wires have some parts in common, and by understanding the parts of it, you will understand how wiring is used in control circuitry.

Conductor

• Inside the control wire is the conductor. This is usually made out of copper. This is a time honored material for making wires, since it is a very good conductor of electricity. Furthermore, it is bendable, and has good longevity if not exposed to corrosive environments.

Insulator

• Around the conductor is an insulator. This is a tube of flexible plastic, and the conductor is inside the tube. An insulator stops electricity. Engineers and designers of control wiring systems do not want one signal voltage to cross over into another wire, so insulated wires are used.

Eyelets

• Sometimes a control wire is just soldered on to a terminal of a sensor. Many times, however, the sensor must be removable. If this is the case, terminal ends are used. One type of end is called an eyelet. An eyelet is a thin tube with a washer-like appendage. The wire is stripped of insulation, leaving about a quarter of an inch of bare copper exposed. The bare copper wire is pushed inside the tube, and a tool called a crimper is used to mash the tube onto the wire. This creates a solid bond. A small screw is placed through the washer part, and it is screwed down securely to a terminal block on the sensor.

Labels

• You must realize that control wires are not just one or two wires, but perhaps hundreds running side by side. Keeping track of what wire goes to what sensor is next to impossible without labeling the wires. Special wire labels are developed, measuring about half an inch wide by about an inch long. They are made of durable plastic, with a sticky side. The non-sticky side has numbers or letters printed on them, so a technician can peel them off a backing paper, and wrap the label around a wire. In its programmable thermostats for home use, Honeywell recommends using labels to mark the wires.