This must be a prank question because the service panel ground wire is a bare wire. There is nothing to catch fire as there is no insulation covering the wire. If not a prank question please give more detail as to what is happening.
Yes a ground wire can cause a spark and cause fire
It means a wire in the ground.
That Thermostat is LOW voltage. IT does not have a ground wire. There is no need for a ground. it only opperates on 24 volts. there may be a green wire but it does not mean it is a ground
If there is no ground wire connect the ground wire to the neutral wire.
Check the continuity of the ground wire from both the ends. Ensure the ground wire is properly connected to earth / ground terminals
If you are connecting 120 volts, you connect the black wire to the breaker, white wire to the neutral bar, and ground wire to the ground bar. If you are connecting 240 volts connect the black & white wires to the breaker, & ground wire to the ground bar.
Yes, if there in no ground wire that is acceptable on a home with no ground wires.
If the voltage between real ground and the ground wire is not 0.0000 Volt, then the wire is not grounded properly.
Some older wire does not have a ground. All you can do in that case is use a jumper wire to connect the ground to the neutral.
Most all vehicles these days are negative ground so, if you touch a positive wire/terminal or cable to ground you can cause damage and possibly start a fire.
the hot wire goes to the starter and the ground wire bolts to the engine block.
The electricity from lightning will follow a wire from the lightning rod to the ground.