Mostly home electricity is provided with two hot wires and one neutral coming into them which supplies you a voltage of 240/120 volts. However, the basic voltage is slightly less which is around 230/110 volts. This power supply is called single phased power.
You might be aware of alternating current which is taught in physics. So, the power coming to your home is indeed alternating. In common language, alternating current allows electricity to be transported along long distances. Hence, it is feasible for the power department to provide you with electricity.
Now coming to wiring systems again, if you notice only one hot wire along with neutral then you might be getting a power of only 115 volts. It all depends on the wiring system. This type of wiring, however, is mostly seen in electrical devices. Few exceptions like dryer or hot water tanks use both hot and neutral wires use up to voltage of 230 volts.
Basic things to know before working on them
I know, this is highly fascinating but do not tear your electrical devices to see the wiring or your residential power supply because it can be life threatening. Always remember to switch the circuit off before working on them even if the power is down. Keep your contact voltage tester with you. Look at the wirings carefully, it is highly possible to have more than one circuits in a single box. Find the one that you switched off. Wiring system is complex so do not rush and double check yourself.
Working with electricity is dangerous than any task and comes with unfavorable outcomes. So, wear safety gears. If you do not have one then simply wear rubber slippers. They will protect you from electric shocks.
Secondly, every home is provided with a “main service panel” which contains circuit breakers or fuses for maintaining the electricity at your home. Whenever power goes off, check the service panel because in case it might be disconnected.