Wire Harness Natural Damage

The circuit group provides a total of service equipment for a certain load source group, such as relay line, switching device, control system, etc. The basic research content of the theory is to study the relationship between the traffic volume, the call loss and the capacity of the harness. The wiring harness is an important basic concept in the theory of communication.

The load source is the service object of the harness, usually the user device; In a broad sense, the upper level device is the load source for the next level of equipment. In telephone communication, the load source is also called the source, and the number of service devices in the wiring harness is called the wire harness capacity. The capacity of the harness is V, which provides services for N load sources. Any source that emits a call can occupy a free service device in a wire harness.


To facilitate the installation, maintenance, to ensure that electrical equipment can work under the worst conditions, the whole vehicle electrical equipment used in different specifications, different colors of wires through reasonable arrangement, the one, and the insulation tied into a bunch of wires, such already complete, and reliable.

2. Normal selection of wire cutting area and color mark

1) the correct selection of wire section area

The electrical equipment in the car selects the area of the wire used in the light of the load current. Electrical equipment for long working hours can be used for 60% of the actual discharge of wire. The electrical equipment used for short work can be used for 60% to 100% of the actual flow of the wire.

2) selection of wire color targets

In order to be easy to identify and repair, the wires in the wire are used in different colors.

In order to indicate the convenience in the circuit diagram, the color of the conductor is indicated by the letter, and the color of its representative is noted in each circuit diagram.

The common failures of the train line are: the contact of the plug parts, the short-circuit between the wires, the breaking of the road, the iron and so on.

There are several reasons for this:

1) natural damage

The electric wire beam is used more than the life time, causes the wire to age, the insulation layer is broken, the mechanical strength is decreased significantly, causing the short circuit between the wires, breaking the way, the iron and so on, causing the electrical wiring bundle to burn.

2) the failure of the electrical equipment caused the damage of the cable bundles

When the electrical equipment is overloaded, short circuit and iron, it can cause the power cable bundle to be damaged.

3) human fault

When assembling or overhauling the parts of the car, the metal objects will crush the electric wire beam, causing the electrical wiring harness to rupture. The battery is connected to the negative pole; When troubleshooting circuit faults, miswiring, shearing wire harness wires, etc., can cause abnormal work of electrical equipment.

Detection of judgment

1) detection and judgment of electric wire beam burning fault

In the circuit of the power system, where to take the iron, the electric wire harness will be burned to where, the junction between the burning and the intact parts can be regarded as the electric wire; If the electrical wiring is burnt to the wiring part of an electrical equipment, it indicates that the electrical equipment fails.

2) detection and judgment of short circuit, broken road and malfunctioning faults between lines

The electric wire harness is subjected to external extrusion and impact, causing the insulation layer of the electric wire to be damaged, resulting in a short circuit between the wires.

When judging, electrical wiring harness plugs at both ends of the electrical equipment and control switch can be disassembled, and the short circuit of the circuit is detected by a meter or test lamp.

- wire breaking fault, except for obvious fracture phenomena, common faults occur between wires and wire terminals. After some wires are broken, the outer insulation layer and the wire terminal are intact, but the inner core wire and the wire terminal are broken. In the judgment, the tension test can be done to the suspected line and the wire terminal. During the tensile test, the conductor can be confirmed that the wire has been broken.

- line contact is not good, the fault occurs in the plug. When the fault occurs, the electrical equipment will not work properly. Judgment, through to the electrical equipment power supply, touch, or pull the plug of electrical equipment, when touching a plug device, the electric equipment work normally, not normal, show that the plug is defective.