Shock

Electrocution can be a painful, and even fatal result of repairing electrical or electronic devices. The lower a Sim's mechanical skill level is, the more likely electrocution becomes, but it can happen even to Sims whose mechanical skill is high. It can also be triggered when the Sim is standing in a puddle while doing the repairs. Sims can call a Repairman to avoid this possible death, though there is a small chance that the Repairman will also be electrocuted.

The Sims
In The Sims, Sims have a high chance of repairing an electrical object with low mechanical skill. This chance decreases, but never drops to zero, as mechanical skill increases. Sims are also guaranteed to get electrocuted when repairing an electrical object whilst standing on a puddle. When a Sim is electrocuted, they are guaranteed to die and cannot be saved.

The Sims Bustin' Out (on console)
In The Sims Bustin' Out on console, one item in electronics is a bug zapper. An adult Sim has the option to "Touch" a bug zapper, and can be electrocuted, but will not die. It does increase their energy motive and decreases other motives.

The Sims 2
In The Sims 2, electrocution causes a large drop in all of a Sim's needs. If this puts three or more of the Sim's needs at extremely low levels, they will die. Sims who survive electrocution get the "Shocked" memory. Their hair will be burnt after being electrocuted, and their faces will be smudged. This can be fixed by bathing or showering or using the "Change Appearance" option on a mirror. With the addition of Influence in the University expansion pack, it is possible for non-controllable Sims to be electrocuted when Influenced to do repairs. Seasons adds the further risk of being electrocuted by lightning, and Open for Business expansion adds the risk of a Servo running amok and electrocuting anyone who is on the lot.

In The Sims 2 (console), Sims with low mechanical skill can also get electrocuted while operating a DJ machine. Usually this will happen while deploying the machine effects (laser, fog, and fireworks). This will also cause the Sim to die.

The Sims 3
In The Sims 3, Sims get the singed moodlet after getting electrocuted for the first time. The lightning will cause the Sim to have burned clothing and messed up hair. If the Sim gets electrocuted again while the singed moodlet is present the Sim will die. The electrocuted ghosts look yellow and have electric currents in their body. Sims usually become electrocuted if they try to repair an object with a low handiness skill, or if an upgrade fails on an object. Sims have a higher chance of getting electrocuted if they are also standing in a puddle of water while attempting to repair an electrical object.

To kill a sim by electrocution easily, you don't have to wait until an electronic object becomes damaged. You could just choose a sim with a technophobic trait, let the sim sabotage an electrical object, then let the sim pee near the object and finally, let that sim repair.

The Sims 4
In The Sims 4, Sims can be electrocuted when they're repairing electronic objects with a low mechanical skill, or when they're repairing an electrical object whilst standing on top of a puddle of water. A Sim will get the Singed moodlet when they get electrocuted, which will give the +40 dazed emotion (for 4 hours), and causes smoke to pour out of the Sim. There is also a chance the object the Sim was repairing catches fire. If the Sim get electrocuted again with the moodlet, they'll die immediately.

For example, if a refrigerator breaks, it will create a puddle of water in front of it. This is dangerous, because Sims can now get electrocuted very easily while repairing it, so make sure a Sim mops up the puddle before repairing the fridge.