Is poking a knife into the toaster really dangerous?

SDStaff Q.E.D. replies:

Just guessing, Gary, but it sounds like you think that electrocution by toaster is a silly female superstition and that manly men have nothing to fear. Perhaps we can also guess your feelings about seat belts, sunscreen, and motorcycle helmets. Luckily, owing to generations of mopes sticking knives into toasters, appliances and house wiring now have safety features built into them to protect guys like you from yourself. But nothing is foolproof, and if you insist on doing your thing with that knife, you’re still taking a chance.

A toaster works by causing a current to flow through a special type of wire with a high resistance to electrical current. The resistance converts the flow of current into heat that browns your bread. As with any electrical appliance, probing a toaster’s innards with a metal item like a fork or a screwdriver entails some risk. You probably think that if the toaster is off, the coils are cool, and no current is flowing, it’s perfectly safe to use a handy butter knife to dislodge your stuck Toast Masterpiece. It’s true that it’s safer than it used to be. If the toaster has a polarized plug and if the outlet it’s plugged into is wired correctly and if the toaster designer put the switch on the hot line (the standard practice), then the risk is small. But I still wouldn’t recommend it. You might slip and accidentally hit the lever and energize the heating elements. You’re also taking the chance that those who installed key elements of the system were as carefree about risk as you are. For example, suppose the outlet isn’t wired right and the hot and neutral lines are reversed–in pre-WWII homes, believe me, that’s far from unusual. The toaster will still operate, but when it’s shut off its coils will remain electrically hot even though they’re cool from a temperature standpoint. If you contact the coils, the toaster might make toast out of you.

Inserting a metal knife or fork when the toaster is unplugged isn’t recommended either. Although there’s no immediate risk of electrocution, you could damage the toaster and create a future hazard. A toaster’s heating coils are usually insulated from the metal chassis by a material called mica. Mica is a mineral with excellent thermal and electrically-insulating properties that make it well suited to this application. However, it’s thin and brittle and if a sharp knife or fork pierces it and allows the coil to contact the chassis, you could cause a short leading to a blown fuse or, even worse, an electrically hot metal frame that could shock or electrocute someone.

Does that happen often? No, but it happens. The Consumer Products Safety Commission estimates that on average 15 people are electrocuted in the U.S. annually due to faulty or misused home electrical appliances, including toasters. Why take a chance on being the 16th? If toast gets stuck, unplug the toaster, open the crumb door on the bottom, and use something dull and nonmetallic such as a wooden spoon handle to push the toast out from the bottom.

Some other electrical safety tips: Inspect cords periodically for damaged insulation or exposed wire and replace those in bad condition. If you get a shock from an appliance, unplug it immediately and don’t use it until you’ve corrected the problem–and remember, given the redundant safety features of today’s appliances, a shock probably means you’ve got multiple problems, e.g., a faulty appliance plus an improperly wired outlet. Finally, never clean an appliance by immersing it in water–even after you dry it, water can be trapped in small spaces inside, providing a path from electrically live surfaces to metal parts you might come into contact with. The risk might not bother you, but why endanger friends or family?

SDStaff Q.E.D. Straight Dope Science Advisory Board

Send questions to Cecil via cecil@straightdope.com.

STAFF REPORTS ARE WRITTEN BY THE STRAIGHT DOPE SCIENCE ADVISORY BOARD, CECIL’S ONLINE AUXILIARY. THOUGH THE SDSAB DOES ITS BEST, THESE COLUMNS ARE EDITED BY ED ZOTTI, NOT CECIL, SO ACCURACYWISE YOU’D BETTER KEEP YOUR FINGERS CROSSED.