How to Wire Sockets in Sequence (Daisy-Chain or Parallel)
Understanding how to wire electrical outlets correctly is crucial for safety and functionality in any home wiring project. While the term "series" is sometimes incorrectly used, standard household electrical outlets are wired in parallel, often referred to as wiring "in sequence" or "daisy-chaining." This method ensures that each outlet receives the full voltage from the circuit. Wiring standard outlets in true series would cause the voltage to be divided among them, preventing appliances from functioning correctly and creating a potentially hazardous situation where the circuit is broken if any connected device is off or disconnected.
This guide explains the standard method for wiring outlets in sequence (parallel), incorporating the details from the provided reference. Always consult a qualified electrician and turn off the power at the breaker before starting any electrical work.
In parallel wiring, each component (like an outlet) is connected across the power source, receiving the full voltage independently. If one component fails or is turned off, the others remain powered. This is essential for outlets so that multiple appliances can be plugged in and operate simultaneously at the correct voltage.
In series wiring, components are connected end-to-end in a single path. The current flows through each component in turn, and the voltage is divided among them. If one component fails or is turned off, the entire circuit is broken. This method is unsuitable and unsafe for standard outlets used for powering appliances.
Standard Wiring Method: Daisy-Chaining Outlets (Parallel)
Daisy-chaining is the most common way to wire multiple outlets on a single circuit. Power comes from the electrical panel to the first outlet box, and then wires continue from the first outlet box to the second, from the second to the third, and so on.
Here's a breakdown of the process, referencing the described method:
Essential Connections
For each standard outlet, you need to connect three types of wires:
- Hot Wire: Carries the electrical current (typically black or red). Connects to the brass or darker colored screw terminals.
- Neutral Wire: Returns the current to the source (typically white). Connects to the silver or lighter colored screw terminals.
- Ground Wire: A safety wire connected to the earth (typically bare copper or green). Connects to the green screw terminal on the outlet and the metal box (if applicable).
Wiring Process for Daisy-Chaining
Wiring outlets in sequence involves connecting the incoming wires from the power source (or previous outlet) to the terminal screws on the current outlet and then running new wires from the same set of terminals (or via pigtails) to the next outlet in the sequence.
Here’s a step-by-step look:
- Incoming Wires: A cable containing hot, neutral, and ground wires enters the first outlet box. These wires connect to the first outlet.
- Connecting to the Outlet:
- The incoming hot wire connects to one of the brass screws.
- The incoming neutral wire connects to one of the silver screws.
- The incoming ground wire connects to the green screw.
- Outgoing Wires (Daisy-Chaining): To continue the circuit to the next outlet, you need to connect another set of wires (a new cable) to the same outlet's terminals or by using pigtails.
- A new hot wire (from the cable going to the next outlet) connects to the other brass screw terminal on the current outlet.
- A new neutral wire (from the cable going to the next outlet) connects to the other silver screw terminal on the current outlet.
- A new ground wire (from the cable going to the next outlet) connects to the green screw terminal, often using a wire nut to combine the incoming, outgoing, and a short wire (pigtail) to the outlet's green screw, as mentioned in the reference ("We've got a pigtail off of our ground for the outlet here").
- Repeating the Process: The cable going out from the first outlet now carries power to the second outlet box. You repeat steps 2 and 3 at the second outlet, connecting the incoming wires to the second outlet's terminals and running a new cable out to the third outlet (if any).
- Last Outlet: The last outlet in the sequence will only have an incoming cable. The wires are connected to the terminals (hot to brass, neutral to silver, ground to green), but no wires run out to another outlet.
The reference specifically highlights:
- "white wire going out to the next Outlet. Again on our silver screw." This confirms the neutral wire is extended from the silver screw of one outlet to the silver screw of the next, which is characteristic of parallel wiring.
- "We've got a pigtail off of our ground for the outlet here." This indicates that the incoming and outgoing ground wires are joined together (often with a wire nut), and a separate short wire (pigtail) connects this junction to the ground screw on the outlet itself. This is best practice for grounding.
Daisy-Chaining Wire Connections Summary
| Wire Type | Color | Connects To (Outlet Terminal) | Daisy-Chain Method |
|---|---|---|---|
| Hot | Black / Red | Brass/Dark Screw | Incoming wire to one brass screw; Outgoing wire to the other brass screw (or pigtail) |
| Neutral | White | Silver/Light Screw | Incoming wire to one silver screw; Outgoing wire to the other silver screw (or pigtail) |
| Ground | Bare Copper /Green | Green Screw | Incoming, Outgoing, and Pigtail to Green Screw (connected via wire nut) |
Important Considerations
- Wire Gauge: Ensure the correct wire gauge is used based on the circuit breaker's amperage.
- Box Fill: Do not overfill electrical boxes with too many wires.
- Terminal Types: Some outlets have screw terminals and push-in terminals. While push-in terminals for hot and neutral can be used, screw terminals are generally preferred for their reliability, especially when daisy-chaining multiple wires or using pigtails.
- Load Capacity: Be mindful of the total load on the circuit when adding multiple outlets.
By following the standard parallel wiring method (daisy-chaining), you can safely and correctly wire multiple outlets on a single circuit, ensuring each receives the necessary power.
