## Introduction Once you understand where the series path runs through a mixed circuit, the next step is to find the parallel portions. Parallel branches show up in lighting circuits, control indicator lamps, load banks, and anywhere the system needs multiple components to operate independently. Being able to spot these branches quickly helps you predict voltage behavior, current division, and the location of faults. Technicians who can identify parallel portions at a glance save time on troubleshooting and reduce the chance of replacing parts that are not actually bad. ## Key Concept A **parallel portion** is any section of the circuit where current splits into two or more separate paths and later rejoins at a common point. Each branch sees the same voltage because all branches connect directly across the same two nodes. In a parallel portion: * Voltage is the same across each branch. * Total current is the sum of branch currents. * A fault in one branch does not automatically shut off the others. > [!info] Branch Basics > A branch is a complete path from the splitting node to the rejoin node. Each branch has its own load and its own current. ## How It Works Identifying parallel portions is mostly about noticing where the conductor divides and how the branches reconnect. Here is the step-by-step approach. 1. **Find the first split** Starting from the series section, follow the conductor until you see it divide into two or more paths. This node is the beginning of the parallel portion. 2. **Trace each branch** Each branch must form a complete path back to the rejoin point. Follow each path all the way through its components. If the path dead-ends or does not reconnect, it is not a parallel branch. 3. **Locate the rejoin point** All true parallel branches connect back to a common node. This return node reunites the divided currents into a single path again. 4. **Check for equal voltage** Because all branches connect between the same two nodes, they all share the same voltage. This is the defining feature of the parallel portion. 5. **Look for independent operation** If one branch fails open and the others keep operating, you are dealing with a parallel layout. This independence helps you verify you have correctly identified the parallel part. > [!tip] Two Points Rule > Anything connected between the same two points is in parallel, even if the schematic is drawn in a confusing layout. ## Real-World Application A common example is a set of indicator lamps used to show equipment status. After a control relay closes, the output splits into several branches, each feeding its own lamp. If one lamp burns out, the remaining lamps stay lit. This behavior tells the technician the lamps are wired in parallel. Another example is an industrial lighting circuit. The breaker and switch are in series, but each fixture downstream is connected across the same hot and neutral. Even if one fixture fails, the rest stay energized because each fixture is part of its own branch in the parallel portion. Parallel portions also show up in resistive load banks, where multiple resistors are wired side by side to achieve a specific equivalent resistance. Identifying these branches is essential for calculating current distribution and total power. ## Safety Notes Parallel circuits can remain partially energized even when one branch is disconnected. A technician may remove a load assuming the circuit is dead, but the remaining branches may still carry dangerous voltage. Follow NFPA 70E approach boundaries and verify voltage at each branch point. Use insulated tools and avoid touching exposed terminals, especially when dealing with lighting circuits that share a neutral. > [!warning] Shared Nodes > A shared neutral in a parallel circuit can still be energized from another branch. Always test before touching. ## Summary Parallel portions are the sections of a circuit where current divides into multiple independent paths. The branches begin at a splitting node and end at a rejoin node, and each branch sees the same voltage. Recognizing these portions makes it easier to map mixed circuits, calculate branch currents, and diagnose faults correctly. Once you can clearly identify both the series and parallel parts of a circuit, you are ready to learn how to reduce and analyze them using a step by step method. <!-- ### Recommended Visuals 1. Diagram showing a main conductor splitting into multiple branches and rejoining later. 2. Annotated schematic highlighting the splitting and rejoin nodes clearly. 3. Example lighting circuit with several fixtures connected in parallel across the same two nodes. 4. Side by side comparison: series path vs parallel branches in different colors. 5. Illustration showing equal voltage measurements across each branch using a meter. 6. Photo of a control panel with multiple indicator lamps wired in parallel. 7. Troubleshooting sketch showing an open branch while the others continue operating. --> > [!columns] > >[!info] Previous lesson > ⬅️ [[3.2 Identifying Series Portions]] > > >[!info] Next lesson > ➡️ [[3.4 Step by Step Reduction Method]]