PseudonymousEd Looks At Project Zomboid Code 02: Flaming Generators

Despite what a lot of people think (and what the wiki used to say), in build 41.53 generators have a chance to catch fire once the condition drops to 20% or below.  

                if (this.condition <= 20) {
                    if (Rand.Next((int)10) == 0) {
                        IsoFireManager.StartFire(this.getCell(), this.square, true, 1000);
                        this.condition = 0;
                        this.setActivated(false);
                    } else if (Rand.Next((int)20) == 0) {
                        this.square.explode();
                        this.condition = 0;
                        this.setActivated(false);
                    }
                }

For more details, watch the video!

Edit 2022-01-10: As of build 41.65, generators are still safe until you hit 20% condition or worse.