How do extension cables or power strips supply power for 3 plugs if they’re only plugged into 1 outlet?

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How do extension cables or power strips supply power for 3 plugs if they’re only plugged into 1 outlet?

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Anonymous 0 Comments

(Note: the discussion below uses the U.S. 110 volt electrical standards to describe things. Other places use 240 volts as the standard voltage, but the principle is the same.)

Another thing to note is that the usual 15 amps mentioned in these comments is the *total* amount of electrical energy that can be supplied to *all the wall outlets* that are on the same circuit, *not* for each outlet individually. The wires in the wall are chained to serve multiple outlets, and there is just one 15A circuit breaker for all of them on a given circuit. So if you have an electric space heater in one room, and plug another one in in another room, if they are both on the same circuit you may exceed the load and the circuit breaker will trip, preventing a fire from overheated wiring.

So your power strip is simply adding more outlets to a circuit with fixed capacity. It can’t give you any extra capacity, just more places to plug devices in. And as long as those devices don’t require much power, like desk lamps, phone chargers or most computers or TVs, you’re not going to exceed the circuit’s capacity.

Most homes will have many circuits to split that load up evenly throughout the house. Half the bedrooms might be on one circuit, the other half on another circuit. The upstairs bathrooms are usually on a separate circuit with GFCI outlets that reduce the chance of a shock if a device is exposed to water. And so on. A good installation will provide a description for what each circuit services on the circuit breaker panel’s door, but that’s not always done.

Per the electrical code, typical residential outlets in living areas and bedrooms are 15A circuits, but in kitchens and laundry rooms they are generally 20A circuits with thicker wiring in the wall to allow for multiple larger appliances running at the same time. Very high-demand appliances such as electric ranges, ovens and electric dryers will each have a dedicated outlet and circuit with 30A capacity (or more), and will be wired to provide 220 volts instead of the typical 110 volts. Their sockets and plugs will also be different to prevent accidentally using a 110v device on a 220v circuit.

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