Which color is live wire?
The protective ground is green or green with yellow stripe. The neutral is white, the hot (live or active) single phase wires are black , and red in the case of a second active.
Chapter 2 - Color Codes
|Protective ground||PG||bare, green, or green-yellow|
|Line, single phase||L||black or red (2nd hot)|
- Neutral colors include black, white, gray, and sometimes brown and beige. They are sometimes called “earth tones.” In Circus, Georges Seurat uses many different neutral colors. You can see a few glimpses of red, blue, and yellow in this painting.
- In AC power supply, there are two symbols L and N. N is Neutral while L is Live or Line? N is Neutral: Does it mean this wire is connected to ground and so it always 0V compared to ground. L is Live or Line: what does it mean? Thanks!
- One side of the receptacle has (2) brass screws and the other side has (2) silver screws. The hot side of the circuit (black wire) should be wired to the brass screws while the neutral side of the circuit (white wire) should be wired to the silver screws. You only need to connect to (1) screw on either side.
The faceplate of a single, one-way switch has two terminals: "L1" is the terminal to which the neutral core wire is attached - the blue wire (traditionally black, before the change). "COM" or "Common" is the terminal to which the live core wire is attached - this is the brown wire (formerly red).
- Wiring a One Way Switch. A one way light switch has two terminals which is a common marked as COM or C. The common is for the live wire that supplies the input voltage to the switch. The other terminal is marked as L1 and is the output to the light fixture.
- A standard 2-wire lighting circuit is shown in Figure 1. The brown wire is Live (also know as permanent live), this brings the live supply to the switch. The blue wire is known as the Switched Live and takes power to the light. Switched Live is only live when the switch is on (this is where it gets its name from).
- In the traveler system, also called the "common" system, the power line (hot, shown in red) is fed into the common terminal of one of the switches; the switches are then connected to each other by a pair of wires called "travelers" (or "strappers" in the UK), and the lamp is connected to the common line of the second
USB stands for Universal Serial Bus, and there are four wires inside of it — usually, it's a red, green, white, and black cord. Each of these wires has a corresponding code: Red color indicates the positive wire with 5 volts of DC power. Black has always been the ground wire in almost all electronic devices.
- The solid/dashed lines on wires like the ones pictured in your question are used to indicate polarity e.g. for the "wall wart" power supplies. Usually* the wire with the white stripe or the dashed lines carries the "positive" (+) end, while the other, unmarked wire carries the "negative" (-) end.
- The Standard-B is used at the device side. Since USB 2.0 and USB 3.0 ports may coexist on the same machine and they look similar, the USB 3.0 specification recommends that the Standard-A USB 3.0 receptacle have a blue insert (Pantone 300C color). The same color-coding applies to the USB 3.0 Standard-A plug.
- USB means Universal Serial Bus. It is a standard and its initial purpose were to replacing the multitude of connectors at the back of PCs. It uses four shielded wires, two of them for power and the other to for data transmission. If you connect two resistor at data+ and data – then you have charging cable.
Updated: 4th October 2019