The labels on the outer sheathing of NM cable indicate the size, or gauge, of the individual conducting wires, the wire material, the number of wires contained inside the cable, the maximum voltage rating, and whether there is a ground wire present. The wire size and number of wires are indicated with numbers.

How do you read a wire code?

An electrical cable is classified by two numbers separated by a hyphen, such as 14-2. The first number denotes the conductor’s gauge; the second denotes the number of conductors inside the cable. For instance, 14-2 has two 14-gauge conductors: a hot and a neutral.

What is L and N wiring?





The N & L stand for Neutral and Load. With your AC line in you should have three wires. Neutral, Load, and Ground. If your wires are color coded for the US then the black wire is Load or Hot, the white wire is Neutral, and the green wire is Ground.

What does the B in NM B stand for?

Non-Metallic Sheathed Cable

Description. Type NM-B (Non-Metallic Sheathed Cable) is commonly used for residential wiring of luminaries, devices and appliances.

What color wires are L and N?

US AC power circuit wiring color codes

Function label Color, common
Protective ground PG bare, green, or green-yellow
Neutral N white
Line, single phase L black or red (2nd hot)
Line, 3-phase L1 black

What are the 3 types of wires?





Three types of wire used are :

  • live wire ( Red colour)
  • neutral wire(Black colour)
  • earth wire (Green colour)

What type of wire is Romex?

Romex Cables

Romex™ is a common type of residential wiring that is categorized by the National Electrical Code (NEC) as underground feeder (UF) or non-metallic sheathed cable (NM and NMC). NM and NMC conductors are composed of two or more insulated conductors contained in a non-metallic sheath.

What are the blue and brown wires?



The blue wire also referred to as the neutral wire, has the function of transferring electricity away from the appliance. The brown wire, otherwise known as the live wire, transfers electricity to the appliance. The combination of these wires is referred to as a circuit.

What does U and V stand for in electricity?

Both of voltage description “U” and “V” are proper, however it must be mentioned that in European notation “U” describes voltage source while “V” describes rather voltage potential. It means that U = V1 – V1 (voltage is a difference between voltage potentials).

What does T stand for in electricity?

Electrical Characteristics

Quantity Symbol Basic Unit
Capacitance C farad (F)
Inductance L henry (H)
Frequency f hertz (Hz)
Period T second (s)

What do the different color wires mean?



Blue and yellow wires are sometimes used as hot wires and as travelers, green wires (and bare copper wires) are ground wires, and white and gray wires are neutral. However, all electrical wires, regardless of their function, may carry an electrical current at some point and should be treated with equal caution.

Does neutral wire have power?

Neutral wire carries the circuit back to the original power source. More specifically, neutral wire brings the circuit to a ground or busbar usually connected at the electrical panel. This gives currents circulation through your electrical system, which allows electricity to be fully utilized.

How do I know which wire is ground?

How to Identify the Ground Wire

  1. Green – In the USA, most ground wires will be green, or at least primarily green.
  2. Green & Yellow – Some systems will use a green wire with a yellow stripe for the ground.
  3. Bare – If the wire is not primarily green, it may also just be a bare copper wire.

Can I tie the neutral and ground together?



No, the neutral and ground should never be wired together. This is wrong, and potentially dangerous. When you plug in something in the outlet, the neutral will be live, as it closes the circuit. If the ground is wired to the neutral, the ground of the applicance will also be live.

Which wire is positive brown or blue?

Brown is your hot wire so you want to connect that to your building’s black wire. The blue is negative or return, so that will go to white.

Which wire is hot if both are black?

The black wire is the “hot” wire, it carries the electricity from the breaker panel into the switch or light source. The white wire is the “neutral” wire, it takes any unused electricity and current and sends it back to the breaker panel.

Can you put two black wires together in an outlet?

It is safe to have two black and two white wires in an outlet provided each wire is correctly attached to the terminal and insulated from contact with other wiring.

What happens if you mix up hot and neutral wires?



This happens when the hot and neutral wires get flipped around at an outlet, or upstream from an outlet. Reversed polarity creates a potential shock hazard, but it’s usually an easy repair. Any $5 electrical tester will alert you to this condition, assuming you have a properly grounded three-prong outlet.

Can you put two black wires together?

This is the typical way to connect a switch. The 2 blacks connected are “power in, power out” to the next switch in the circuit. The pig-tail to the dimmer connected to the two blacks is also typical.

Which wire is hot when both are same color?

In most modern fixtures the neutral wire will be white and the hot wire is red or black. In some types of fixtures, both wires will be the same color. In this case, the neutral wire is always identified by some means.

What happens if you connect white wire to black wire?

If you see both sides connected together, it means it’s a switch loop. The white wire that’s connected to the black wire carries power to the switch. And the black wire that’s in the same cable carries back that switched power to the outlet. But keep in mind what you should do when the wires are connected.