is bad connection caused surge voltage?

Answer 1

Your question makes no sense, are you asking if a bad connection causes surges or are you asking if a bad connection is caused BY surges? A surge can cause a connection to go bad. This is exactly what happened to the cryo tank heaters in the Apollo 13 spacecraft which caused the heater thermostat contacts to weld closed. Yes, a surge can cause damage to connections and to items exposed. Surges come from a large load suddenly going OFF, such as a large motor under heavy load. The magnetic field in the motor causes a huge voltage spike (also known as an inductive kick) as the contacts open, which is why you get a spark which will eventually cause pitting and the contacts to fail. What a number of people call a surge is actually the opposite. The dimming of the lights is what I am talking about. That is actually a low voltage condition, which comes from a heavy load starting, like a refrigerator motor.

Answer 2

Surge voltage means a surge of higher voltage leading to a burnout (general result). It can happen if you have inductive loads in the circuit since the bad connection causes a surge due to the change of current through the inductance (remember how a tube light starts glowing)