The distinction between series vs parallel circuits is one of the most fundamental things you need to understand about electricity. In this article, you will learn all the basics you have to know about wiring in series vs parallel. In general, common wiring in buildings is parallel because it is safe and reliable, while series wiring is only used for limited applications. Both are closed electrical circuits, but the similarities between them end there.

What is a Series Circuit?

A series circuit stands for a closed circuit where the current follows one path. In a series circuit, components are connected end-to-end, forming a single path for current flow. The same current flows through each component. If any component is broken or removed, the entire circuit stops working. This creates a situation where the total voltage across the circuit is the sum of the voltages across each component. 

What is more, the total resistance in the series circuit is the sum of individual resistances. Higher total resistance means less current flow. 

Series circuits are not commonly used in households, commercial, or industrial wiring. One of the examples of its application is the traditional string lights. If one bulb of such a string light goes out, the entire string often stops working. Series wiring can also be used for some batteries.

What is a Parallel Circuit?

A parallel circuit is the most common circuit for household items and the most common type of electrical circuit in general. This is the circuit where the current divides into several branches before returning and completing the entire circuit. 

In a parallel circuit, components are connected across common points or junctions, creating multiple paths for current flow. Therefore, the total current is the sum of the currents through each parallel branch. Each component in parallel has the same voltage across it. What is more, the total resistance is less than the smallest individual resistance. Parallel circuits reduce overall resistance, increasing current flow.

The clearest example of a parallel circuit is household wiring. All outlets, switches, and lighting circuits are a part of a parallel circuit. If one appliance is turned off, others will continue to work. The appliances in a parallel circuit are merely connected to the main current flow.

Main Differences Between Series and Parallel Circuits

• In a series circuit, the current is the same through all components; in a parallel circuit, it divides among the paths.
• In series circuits, a fault in one component affects the whole circuit; in parallel circuits, other paths usually remain unaffected.
•  Series circuits are simpler but less reliable for large networks, while parallel circuits are more complex but ensure a consistent power supply.
• Parallel wiring is generally more reliable. If one component in a parallel circuit fails, others can continue to operate.

Why Would You Use Series Wiring?

After comparing series and parallel circuits, one question remains: why would anyone use series wiring if it is unreliable and outdated? The truth is that series circuits have limited applications where their construction is a benefit.

A specific example of series wiring is when a ground-fault circuit interrupter (GFCI) receptacle can be used to protect additional standard receptacles that are located downstream from it in what essentially is series wiring. If the GFCI terminal malfunctions, all other terminals will also cease working.

Power strips, blocks of electrical sockets that attach to the end of a flexible cable, also use a form of series wiring. They have one switch that controls several appliances and devices connected in parallel. Turning off the power strip switch cuts power to all devices plugged into it, similar to a series circuit's behavior where interrupting the flow at one point affects the entire circuit.

Series wiring is also common inside batteries. Battery packs are connected in series inside consumer electronics, electric vehicles, and electronic portable devices like cameras and flashlights. Finally, when studying electricity, series circuits can be used as a demonstration tool for educational purposes.