It could blow up the battery.
you may have a dead battery of a shorted wire or component. be sure to connect positive to positive and negative to negative. disconnect one component at a time to find short. check that the exaust manifold isn't touching the starter
The wire will get hot, the temperature it gets up to will depend on the ampere of the battery and size of wire. The wire can get hot enough to causes burns or start a fire if the battery is large enough. Why this happens is because you have shorted the battery out. The power comes out of the positive post and back in the negative post. When you short it out the power can flow from one post to the other very quickly causing the short to get hot, due to the amount of flow.
Interior lights being left on Shorted wiring for the starter motor. This is the very first electrical component that receives power from the battery. Any wires that are shorted together (positive & negative tied together or simply touching) will also run down the battery in short order.
A PARASITIC LOAD IS A SHORTED POSITIVE WIRE GOUNDING TO THE NUETRAL ON YOUR AUTOMOBILE BATTERY. A RAW WIRE IS DRAINING YOUR BATTERY. GOOD LUCK TRYING TO FIND IT.
A fuse?
Depending on the age of the vehicle you probably have shorted or grounded the electrical system causing fuse(s) to blow. Question was kind of broad may want to be more specific
A battery cannot be drained by a shorted diode when the ignition key is off.
From the positive battery cable but you must HAVE A FUSE BLOCK OR A SHORTED WIRE WILL CAUSE A FIRE.
only if it's off The plastic body of the battery, or one of the terminals, yes, BUT... disconnected from the vehicle or not, DO NOT allow any metallic object to touch BOTH of the battery's terminals [Positive and Negative] AT THE SAME TIME. This is because that touching both terminals at the same time with any conducting metal such as a wrench will create a SHORT CIRCUIT, and COULD cause the battery to explode, throwing shrapnel and battery acid everywhere for several feet around the shorted battery.
The alternator really can be shorted out but you can cause a short if you contact the hot battery connection to ground. whenever you work on a car, you should really disconnect the negative battery cable. It takes that battery out of harms way and you too.
depends on a lot of things........is your battery shorted out or is it just dead?