Why connect "-" to chasis when jumpstart or charge battery?

[Tigershark1976]

I know that when jump start a car, or charge a battery without disconnecting the battery from the car, the positive should be connect to the positive terminal at the battery but negative should be connected to the chasis instead. Why isnt the negative not connected directly to the negative terminal instead? anyone care to explain??

[Xanavi]

The reason for connecting the negative cable to ground (car body, a bolt in car) rather than to the negative terminal of the dead battery is to minimize the chances of a spark near the battery, where there may be potentially explosive gases.

[Mits_jc]

Is it OK to connect the negative lead directly to the negative terminal of the battery? I've jump started a few times doing that and it's been fine all along.

[Kb27]

Spark and a badly leaking battery with explosive gases is the reason.

When you connect to a chassis point, any spark is at that point, away from the battery.

 

There are many cases of battery exploding.

 

Don't be the one to find out.

[Tigershark1976]

Spark and a badly leaking battery with explosive gases is the reason.

When you connect to a chassis point, any spark is at that point, away from the battery.

 

There are many cases of battery exploding.

 

Don't be the one to find out.

 

 

I c.... thanks! All these while, I tot its to protect the equipment in the car instead.... now I know.... having to say that, I always smoke near to batt... think I better stop now...