ignition switch fire

So generally, theoretically, in any make or model, what can make the electrical side of an ignition switch to smoke and catch on fire? Switch failure and external causes must both be addressed. Please offer insight...I got a kid in this car, I need to know for sure to prevent a major widespread fire, not to mention hitting the road again. Just some ideas please, I've never seen it before now, I am hoping it's simply a bad switch that needs replacing followed by clear skies.

The contacts in the switch probably got loose/corroded/dirty, causing arcing between them. This heats the body of the switch up and makes the problem worse when the hot metal melts the plastic holding it in place.

Switches get dirty, wear out, but commonly get destroyed because of arcing. Typically this is caused by leaving accessories switched on, and operating the ignition switch, on or off. Replacing the switch should solve the problem, but make sure the connectors are in good shape and clean. The blower motor is usually the cause, because it's the biggest amperage draw that goes through the switch. Most other big draw items are on relays. But, get in the habit of turning off all the accessories, and you shouldn't have a problem.

I agree with both of the above posters.

Additional bit of info--the XJ ignition switch, along with a large part of the rest of the electrical system--is grossly over-engineered! Not over-engineered in the old-school sense of built really heavy to last, but the exact opposite, over-engineered to make things as light and cheap as possible.

You can make the ignition switch last longer by reducing sudden loads on it, i.e., turn off all lights, fans, radio, etc. before turning off the ignition switch. That ensures that the next time you start the XJ the load through the ignition will be reduced.

The last swich I had to replace was in my daughter's '93 Sable. The car had Climate Control, so needless to say, the blower was always at full cry when you went to start it. I never in my life saw such a melted lump of plastic as when I had to change it. "Dad, my steering wheel is smoking".

Thanks everyone, sounds like just a bad switch. Just wanted to be somewhat sure that if I replace it with a new one, it won't just flame up right away again, or cause a major fire..