What color should the load wire be?
So, what color is the load wire? Load wires are mostly black, but red can also be used as a secondary load wire. They are also connected to the switch's top half, while line wires are connected to the switch's bottom half.
You simply use the tip of your voltage tester to touch the insulation of each of the wires to be identified. The wire that gives off a beep or light is your line wire and the other wire is your load wire. Making use of a voltage tester is a safer method than making use of a multimeter to identify your wires.
Neutral wires are identified by their white or gray casing. Although they may not always be circulating an electrical current, they should be handled with as much caution as hot wire.
One of the black wires receives power from the service panel; the other sends it on to other loads on the circuit. The white wires allow current passing through the outlet and the other loads on the circuit to return to the panel.
Unfortunately, this color-coding system isn't standardized, and the color system can be confusing. The fact that black is used for both line and load can be daunting. Line wires are generally black, and the load wires are generally red, black, or sometimes blue.
The supply side of the switch is the termination point on the switch where the power source is terminated. Whilst, the load side of the switch is where the cable going to your load/(equipment or electrical appliances) is terminated.
The circuit's hot wire (typically colored black or red) connects to the black or brass-colored screw terminal marked LINE. The white neutral wire connects to the silver-colored screw terminal marked LINE. The markings for line and load usually are printed on the back of the outlet's plastic body.
The “line” wires are the incoming power from the breaker box and the “load” wires are the outgoing power that travels down the circuit to the next outlet.
They are as follows: Red – Red cables carry the positive current. Black – Black cables will be the negative cable. Grey or White – Grey or white cables are the ground wires.
Wire | Colour |
---|---|
Live | Brown |
Neutral | Blue |
Earth | Yellow and Green |
What is a load wire?
Load Wire: This is the wire that connects your switch to your light bulb or other “load” (ie: a fan or other appliance). It is also usually black.
Most homes have two hot wires (line wires) and one neutral wire (load wire). The hot wires are usually colored black or red while the neutral wire is colored white. The line wire is the wire that brings power from the utility company to your home.

The neutral carries current if the loads on each phase are not identical. In some jurisdictions, the neutral is allowed to be reduced in size if no unbalanced current flow is expected. If the neutral is smaller than the phase conductors, it can be overloaded if a large unbalanced load occurs.
In the electrical trades, the terms "line" and "load" are shorthand words that refer to the wires that deliver power from the source to a device (line), vs. those that carry power onward to other devices further along the circuit (load).
In most cases, black can be the line wire and the red wire is the load. Because various nations use different colors, it might be difficult to distinguish between the line and load wire colors in an electric circuit. The quickest approach to determine the line/hot and load wires is to look at the insulation colors.
If you live in the U.S., as per electrical codes, a common wire should be either white or gray. White common wires are seen more often. On the other hand, blue is a commonly used color code for common wires in European counterparts.
If you mix them up there, the GFCI will not function properly, if at all. What's the difference between load, line, and neutral wire? Load wires come from a control device and feed power directly to the controlled appliance or device “load.”
A switch has to have a load wire, otherwise it wouldn't turn anything on and off.
A simple standard electrical circuit has a black or red "hot" wire that carries power from the power source to the device (e.g., switch, fixture, outlet, appliance), a white neutral wire that carries the power back to the power source, and a green or bare copper ground wire that connects the device to the home's ...
Some people take the name neutral to mean that it doesn't have current running through it, but that is not the case. The neutral wire is part of the live circuit, which means anytime it is plugged in, it will likely have electrical current going through it.
Is a red wire hot?
Red wires are commonly used as secondary supply wires alongside black wires, which means that red wires, likewise, are nearly always hot. While many appliances will require only a black supply wire, some larger appliances will require a secondary supply wire, which is sometimes red.
Red: The red wire signifies the phase in the circuit and is the live wire and cannot be connected to another red or black wire. It is often used as a switch leg, in which the wire comes from bottom terminal of the switch and when the switch is turned on, the wire becomes hot.
In a household setting, the most obvious examples of electrical loads include light bulbs and appliances. In a more general sense, any resistor or electric motor in a circuit that converts electrical energy into light, heat, or useful motion constitutes a load on the circuit.
Use a test lamp. It's just a light bulb with two wires coming out of the holder. Touch one lamp wire to one of the black wires and the other lamp wire to the ground wire. If the bulb lights up, the wire is hot.
The electricity flowing through a wire doesn't care about its color. Building codes in some countries mandate that certain wire colors be used or not used. Wire harnesses in vehicles may use color codes consistently (or they may not). But generally, in electronics, it doesn't matter too much.
Black (neutral) Red (live) Green and yellow (earth)
As far as your negative wires go, the white wire is a negative wire. You should connect this one to the negative wire in an outlet or ceiling fan after all the positive wires are connected. The green wire should always connect to the grounding screw or wire, which is usually green.
The negative current must be black. The ground wire, if present, must be white or grey.
- Live wire (L)
- Neutral wire (N)
- Earth wire (E)
Three-conductor wire has two hots — black and red — and a white neutral. Though normally used for three-way switching, three-conductor wire is commonly used for duplex receptacle wiring as well.
What does 3 wire mean?
: a constant potential system of electric distribution in which lamps or other receiving devices are connected between either one of two main conductors and a third wire and motors and heavy duty appliances are usually connected across the main conductors.
Blue = Neutral
The neutral wire colour is blue. The neutral wire transfers electricity away from the appliance to avoid overloading. It is located at the end of the circuit for connection after the electricity has flowed around the live and earth wires.
The positive wire, also commonly called the hot wire, will typically be black in color. It is the source of the electricity. The electrical current travels from the outlet or other power source on the positive wire, so if it is plugged in anywhere, it should be considered a live (and dangerous) wire.
White wire (Neutral) - This wire is usually white in color and connects the neutral wires from your light fixture, junction box and existing switch. Green or Copper wire (Ground) - This wire is usually green in color or bare copper. It comes out of your junction box and connects to a terminal on the switch.
Neutral is the return path of the current, and ground wire holds the fault current to trip the breaker in protecting the person and the facility. The neutral and ground should never be bonded together in the facility except for the main panel.
A neutral wire is a current-carrying conductor that brings current back to the power source to establish control over the voltage. Usually identified by its white color, it takes the unused electricity back to the transformer.
The Code considers the neutral conductor a current-carrying conductor only when it carries the unbalanced current from other ungrounded phase conductors. When circuits are properly balanced, the neutral carries very little current.
The most common way to identify line and load wires is through color. Line wires are typically black or red, while load wires are usually white.
India. The standard for electrical wiring color code in India is as follows. According to the old standard, Red is used for live (or line) power conductor, Black for neutral and Green for protective earth or ground.
An electrical load is simply any component of a circuit that consumes power or energy. In a household setting, the most obvious examples of electrical loads include light bulbs and appliances.
What is the load and what is the feed?
The feed is the cable from your fuse board, supplying the power to the isolator switch. The load is the cable supplying the appliance once you have switched the isolator into the on position.
What are Red Wires? Red wires are usually used as secondary hot wires. Red wires are also hot and should be clearly marked to avoid the dangers of electrocution. Red wires are commonly used when installing ceiling fans, where the light switch maybe.
A black or red-hot wire usually connects to a brass-colored screw terminal or black wire lead on electrical devices. A white neutral wire usually connects to a silver-colored terminal or white wire lead.
US AC power circuit wiring color codes
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.
If wired properly, we can use neutral as ground wire. We cannot use ground as neutral as it doesn't provide the normal return path for the current.
Line/incoming wires are always attached from the bottom to the electrical panel, whereas load cables are connected from the top. You can tell the difference between the line and load wires in the electrical panel by looking at the position of the connected wire on the panel box.
References
- https://www.mistersparky.com/pleasantville/about-us/blog/2022/june/line-vs-load-wire-what-you-need-to-know/
- https://www.quora.com/What-is-meant-by-load-and-supply-on-a-switch
- https://www.mistersparky.com/san-antonio/about-us/blog/2019/june/understanding-the-colors-of-electrical-wires-the/
- https://www.creativesafetysupply.com/qa/wire-marking/what-does-the-neutral-wire-do
- https://www.ecmweb.com/national-electrical-code/code-basics/article/20890526/characteristics-of-the-neutral-conductor
- https://ep2000.com/understanding-neutral-ground-grounding-bonding/
- https://www.thespruce.com/line-and-load-connections-1152729
- https://www.jlconline.com/how-to/electrical/q-a-tracing-3-wire-circuits_o
- https://www.allaboutcircuits.com/textbook/reference/chpt-2/wiring-color-codes/
- https://www.thespruce.com/color-coding-of-electric-wires-1152300
- https://www.quora.com/How-do-you-tell-which-wire-is-hot-if-both-are-black
- https://support.brilliant.tech/hc/en-us/articles/360029365831-Identifying-Wires-on-Your-Old-Switch
- https://www.thespruce.com/line-or-load-gfci-connection-1152785
- https://www.hgtv.com/how-to/home-improvement/how-to-replace-a-standard-outlet-with-a-gfci-outlet
- https://support.wyze.com/hc/en-us/articles/4406495455387-How-do-I-know-if-I-have-a-neutral-wire-
- https://au.rs-online.com/web/content/discovery/ideas-and-advice/wiring-colours-guide
- https://www.creativesafetysupply.com/qa/wire-marking/whats-the-difference-between-a-positive-and-neutral-wire
- https://byjus.com/question-answer/name-the-three-wires-used-to-carry-electricity-from-one-place-to-another-explain/
- https://ewcswire.com/blog/what-do-electrical-wire-colors-mean/
- https://www.rrkabel.com/media-centre/blogs/decoding-the-meaning-behind-wire-colours
- https://electrouniversity.com/how-to-identify-line-and-load-wires/
- https://romanelectrichome.com/electrical-wiring-tips/
- https://uk.rs-online.com/web/content/discovery/ideas-and-advice/wiring-colours-guide
- https://www.mybuilder.com/questions/v/31209/wiring-cooker-via-a-isolating-switch-from-mains-to-switch
- https://www.hgtv.com/how-to/home-improvement/how-to-identify-wiring-in-an-electrical-outlet
- https://www.mistersparkyokc.com/understanding-electrical-wire-colors/
- https://electronics.stackexchange.com/questions/410213/does-wire-color-matter-in-electronics
- https://www.electronicshub.org/ground-vs-neutral/
- https://en.wikipedia.org/wiki/Ground_and_neutral
- https://energyeducation.ca/encyclopedia/Electrical_load
- https://www.angi.com/articles/how-tell-positive-negative-wire.htm
- https://p3connectors.com/electrical-wiring-colours-standards/
- https://www.circuitsgallery.com/how-to-determine-line-and-load-wires/
- https://www.cinchhomeservices.com/faq-library/-/faq/what-is-electrical-common-wire
- https://nassaunationalcable.com/blogs/blog/what-does-the-neutral-wire-do
- https://www.creativesafetysupply.com/qa/wire-marking/what-are-wire-color-codes
- https://kaiweets.com/blogs/news/how-to-identify-line-and-load-wires
- https://www.merriam-webster.com/dictionary/three-wire%20system
- https://www.electronicshub.org/electrical-wiring-color-codes/
- https://www.quora.com/What-happens-if-you-mix-up-line-and-load
- https://community.smartthings.com/t/smart-light-switch-without-load-wire/115691
- https://www.creativesafetysupply.com/articles/wire-color-codes/