A short circuit occurs when positive and negative electrical polarities touch each other, without a suitable electrical device wired into the circuit. When a short circuit happens, your electrical fuse blows, or your cut-off switch trips, stopping the electricity supply getting to the area where the two wires touched other and therefore making it safe to correct the short circuit. Electricity can be extremely dangerous, so if you want to test your fuses, or the trip switch in your fuse box, you need to create a short circuit, but very safely. You can do this by using a low-voltage transformer; you're likely to have one or two transformers in a toy cupboard that are used to operate railroad or car racing sets.
Things You'll Need
AWG gauge 16 wire
Cut two 6-inch strips of wire using a knife. Remove about ¼ inch off the ends of the two strips of wire using wire strippers.
Connect one end of each of the two strips of wire to the terminal connectors on the transformer. You can usually unscrew the connector knobs using your fingers, or if the transformer has screw connectors, loosen the screws slightly using a screwdriver. Insert the wires under the connectors or screws and tighten them using your fingers or the screwdriver.
Plug in a transformer to your electrical socket. Transformers turn high voltage electricity into safe low voltage electricity. Turn on the power to the transformer. If your transformer has a variable voltage selection, then set it to the highest setting; it's only likely to be about 12 volts.
Hold one strip of wire from the transformer in one hand and the other strip of wire in the other hand. Touch the loose ends of the wires onto each other. You've made a short circuit as you have connected the positive and negative polarities together without and electrical device between them. The short circuit back-ups to the electrical socket then to the fuse box or trip switch within a millisecond and your fuse blows, or the cut-off switch trips.
Remove the wires from each other. Turn off the transformer. Reset the trip switch, or replace the fuse.
Do not attempt to directly short circuit an electrical socket as it is highly dangerous. A transformer reducing high voltage electricity to low-voltage electricity; usually no more than 12 volts. Creating a short circuit using the low-voltage electricity it produces has the same effect, but is safe and you get no more than a small spark when the wires touch each other.