Monday, June 2, 2008

Grounding cables for car

Everything involving the electrical systems in your car requires a free flow of electrons from -ve to +ve terminal of the battery (note that the conventional current flow from +ve to -ve used in most circuit diagram is opposite to the actual electron flow).

Good electrical performance requires a grounding system that is capable to carry a lot of current with minimal resistance. Your car's engine control unit (ECU), spark plugs, lights, in-car entertainment (ICE) components, air conditioner, fans, power windows, cigarette lighter, etc. are all working on a complicated electrical network that includes fuses, relays, and electrical cabling, and they all share a common ground. Almost everything that is powered electrically in your car is grounded to the frame or the metallic body of the car. The negative battery terminal is also grounded to the frame, which causes the frame to serve as a gigantic piece of wire in the circuit.

Usually, the stock grounding system of the car consists of just a few non-braided cables that connect the chassis, engine and firewall to the -ve terminal of the battery. The cables are of normal quality only. In addition, as these connections oxidize or come loose over time, the amount of conductive material decreases, and the electrical devices have to work much harder to overcome the increased resistance.

By installing additional grounding cables connecting the various grounding point or point closest to the various components of the electrical system, and link it directly back to the -ve terminal of the battery, the result is: an alternative path is provided for better flow of the electrical current, via the lower resistance paths. The grounded electrical components are expected to work more effectively with better performance.

The current flow will always take the path of least resistance. Therefore, adding grounding cables to your car can only make the different if the additional cables are of higher quality and lower resistance than the stock grounding system.

Characteristic of grounding cable is determined by American Wire Gauge (AWG) specification. The larger the AWG number, the smaller diameter of the wire. For example, 4-AWG cables are better than 8-AWG cables, because they have thicker diameter, lower resistance and higher current carrying capacity.

Grounding cables are good companion to voltage stabilizer, and usually they are installed together to obtain the best performance.


Anonymous said... Reply To This Comment

I quite often get electrical shocked each time close the car door. Will grounding cable improves it?

Voyager8 said... Reply To This Comment


Those are static electric discharge and is a totally different matter.

I'll write a new article for that.


Anonymous said... Reply To This Comment


Voyager8 said... Reply To This Comment


踩 brake 的时候,后尾的 brake 灯会亮,所以踩 brake 也有用到汽车的电路。

至于你的问题,我不是 mechanic,也不清楚,建议你在下次 service 车时叫车厂检查。

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