Automobile manufacturers use of different colors for the different circuit so that defective circuit could be easily located hence, in supplying electricity to different units, different types of are used. If these are left hanging there is every likelihood of short-circuiting and even fire may break out. To avoid all these in automobiles, all the are grouped together, cotton-braided and dipped to the chassis or body. This is known as the wiring harness. While crippling the harness, care should be taken the to avoid fixing up the harness near the exhaust pipe of fuel line.
TYPES OF FOR AUTOMOBILES
To light any bulb or make any electric unit , connecting one positive and one negative along a part is the normal method. It is a practice commonly seen in . When it comes to , the process seems the same. Two will be needed which are the positive and the negative and they are connected in two ways in the automobiles; such connection systems are listed below:
EARTH RETURN SYSTEM
The of a is earthed to the body or chassis which is made of metal. As we know, metal is a good conductor of electricity. Only is taken from the unit via switch and of that unit is earthed, in that way; one complete of is saved. Due to the saving of electric , earth return system is used in almost all present-day vehicles.
DOUBLE POLE SYSTEM
In this system, two wires that are the positive wire and the negative wire are taken from the battery to every unit. The system of wiring is used only in costly vehicles and is compulsory for vehicles which are used for carrying explosives, petrol or oil tanker and in vehicles.
When it comes to , two types of are used and they are:
- THE COTTON BRAIDED : for the copper brand, rubber or plastic is molded on top of it, cotton braided and then varnished to give insulation. These being costly are not much used.
- THE P.V.C. : for the copper brand, the plastic is molded as its insulation. It is cheap and easier to manufacture, hence; it is used commonly than the cotton braided .
GRADES OF & CONNECTIONS FOR
used in automobiles are grades that are, thin or thick according to electric load they have to carry. Manufacturers usually supply in the wiring diagram. The size of used for each circuit such as 14/.010 which means that this particular consists of 14 each having a diameter of .010”.
While replacing new , always use the correct grade of . In the case you used a thinner than the required size, firstly it will not carry the expected load, secondly; light illumination intensity will be affected and thirdly, the is likely going to heat up and melt the insulation leading to electrical shocks because of the overloading in it. The last condition of the could lead to a fire outbreak in any .
In the same way, if you use thicker than the required size, it will increase the resistance and increase the total cost of the wiring.
Based on frequently used sizes of used for , the following grades of are available for such use:
- for the self-starter to switch – 6mm 35/.12 for 12 volts and 8mm 65/.12 for 24 volt
- Headlight and tail light circuit -- 4mm 14/.12 for 12 volts and 6mm 35/.12 for 24 volts
- Roof light, brake light, indicator light – 4mm 14/.12 for 12 volts
- cable 61 21 gauge
- High cable 19/.020
To make connection, the insulation by ½ inch, solder thimble on it and tighten the thimble with the help of screw nut or bolt. In the case of thimble and solder is not available, twist the to make a ring, put a cup washer and tighten with the fastener. Note; under no case, connections should be kept loose.
Originally posted 2018-08-01 13:46:23.
A mechanical engineer and an NDT inspector by profession. However, I love blogging and sharing of knowledge for human intellectual development, especially relating to engineering fields, environment, and science trending updates. “Engineeringall.com” is a platform for any individual with similar passion, to do so; use the “PUBLISH YOUR ARTICLE” page at the MENU to share your personal ideas, researched knowledge, or discovered incidents, etc.to those in the engineering & & the general online communities across the globe. If you love this post please share using the social buttons below.