No disasters?

@Luna1968  There's a 2.5 chance of a burglar appearing each night, from 9 pm to 2 am, but only if all the sims in the household are asleep or away from home.  I believe that sims in the Criminal career are exempt from burglaries.

I only know of two circumstances that can cause an electrocution.  One is if a sim has already tried and failed to upgrade or repair an electrical (not plumbing) appliance and still has a moodlet from it.  The other is if a sim tries to repair an electrical appliance while standing in a puddle.  Handy sims will never fail at either upgrades or repairs and may even be fine while standing in a puddle.

Fires only start for a specific reason, but there are many: cooking, inventing, even lighting a fireplace, to name a few.  (Google can find you more exhaustive lists.)  The chance of a fire is random and different for each action, with some ways to prevent them, for example a stove or fireplace can be fireproof by design or be upgraded, and Natural Cooks will never burn food, let alone set the stove on fire.

There is no way to change the chances of any of this happening without mods, nor to introduce spontaneous chaos, e.g. a "disaster" without a defined cause.

Thank you for your reply! I do not understand why I could play for this long though, and never have any of these things happen!

@Luna1968  I think it's perfectly reasonable that none of these things have happened.  How many times have you had a sim with low cooking skill and without the Natural Cook trait cook a meal on the stove?  How many times have you told a sim to try again to repair an object after they've already been shocked once?  And if your sims regularly stay up past 2 am, you'll never see a burglar.

The point is, each of these bad outcomes has a low chance of happening, so if the events that would trigger them don't happen very often either, it might take real-time months for anything to go wrong.  If you really want more chaos, there are mod-related ways to introduce it.