Asked by: Conceso Schotteldreier
home and garden indoor environmental quality

What does NM mean on electrical wire?

Last Updated: 22nd January, 2020


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Furthermore, what is nm electrical wire?

Understanding NM (Non-Metallic) Sheathed Cable. Sometimes known as "Romex," named for one of the common brand names, NM cable is a flexible electrical cable that features an outer plastic sheathing that protects two or more insulated conductors, as well as a bare copper ground wire.

Subsequently, question is, do electrical wires need to be in conduit? Code requires that romex be installed in a conduit. Conduit also protects your wires from exposed surfaces such as rough bricks in a basement. PVC conduit is easy to cut and to install and will make your wire installation simpler. If your wiring is outdoors, it is very beneficial to run it in an underground conduit.

Thereof, what do the letters on electrical wire mean?

Her's a breakdown to help make some sense of the lettering. The “T” stands for thermoplastic insulated cable. A single “H” means the wire is heat resistant. “HH” means that the wire is heat resistant and can withstand a higher temperature.

How do I identify a wire?

know what each color of wire does in the circuit

  1. The black wire is the "hot" wire, which carries the electricity from the breaker panel into the switch or light source.
  2. The white wire is the "neutral" wire, which takes any unused electricity and current and sends them back to the breaker panel.

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Can you mix aluminum and copper wire?

The only way considered safe to connect copper and aluminum is through a splice connector. Specifically, you have to connect the wires individually so they are not prone to corrosion. The effectiveness of “pigtailing” using twist-on connectors has been evaluated by CPSC staff.

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Should I use 12 or 14 gauge wire?

14-gauge wire is the smallest allowed for the permanent wiring of a circuit. It is rated as able to carry up to 15 amps of current. 12-gauge wire is the next size larger and is allowed to carry up to 20 amps.

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Can I mix 12 and 14 gauge wire?

mixing 14-gauge NM and 12-gauge. both 14 and 12 gauge will be protected by a 15A breaker. Code states that 14Ga will be protected by an overcurrent device of not more than 15A and 12GA by 20A. 14 and 12 are both ok behind a 15amp breaker, but you must use one or the other and not both.

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What does type NM B mean?

1. Indoor NMB cable or Romex® 12/2 cable. NMB stands for Non-Metallic because it has a PVC jacket instead of a metal clad jacket. It is a basic indoor electrical wire used to deliver power from an electrical box to lights, outlets and appliances.

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Can nm B WIRE be put in conduit?

Yes, NM cable can be in conduit. In fact. NEC calls for it to be in conduit, when protection from physical damage is required.

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What type of electrical wiring is used in homes?

The most common type of wiring in modern homes is in the form of nonmetallic (NM) cable, which consists of two or more individual wires wrapped inside a protective plastic sheathing. NM cable usually contains one or more “hot” (current-carrying) wires, a neutral wire, and a ground wire.

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What are the different types of electrical wire?

THHN/THWN letters represent the most common types of individual wires used in residential applications.
  • T – Thermoplastic insulation.
  • H – Heat resistance.
  • HH – High heat resistance up to 194 degrees Fahrenheit.
  • W – Rated for wet locations.
  • N – Nylon-coated to resist damage from oil or gasoline.

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What is TW wire?

TW — Indicates a single conductor having flame-retardant, moisture-resistant thermoplastic insulation. The wire is rated 60°C wet or dry. THHN — Indicates a single conductor having flame-retardant and heat-resistant thermoplastic insulation with a jacket of extruded nylon or equivalent material.

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Can 8 gauge wire handle 50 amps?

8 AWG may carry a maximum of 70 Amps in free air, or 50 Amps as part of a 3 conductor cable. David, if that cable is NM (Romex) then it actually cannot carry 50 amps.

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Can 10 gauge wire handle 40 amps?

“Twelve-gauge wire is good for 20 amps, 10-gauge wire is good for 30 amps, 8-gauge is good for 40 amps, and 6-gauge is good for 55 amps,” and “The circuit breaker or fuse is always sized to protect the conductor [wire].”

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How do I know what gauge my electrical wire is?

Method 3 Gauging Stranded Wire
  1. Measure the diameter of a single wire.
  2. Multiply the wire's diameter by itself.
  3. Multiply the result by the number of strands in the wire.
  4. Find the wire's corresponding AWG value.

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What are the three types of wires?

In the basic there are three types of wire:
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What is 10 gauge wire used for?

12 gauge Romex is rated for 20 Amps and is commonly yellow jacketed. 14 gauge Romex is still used in some applications and is rated for 15 Amps and is grey jacketed. 10 gauge Romex has an orange jacket and is used for water heaters or clothes driers.



What size wire do I need for a 20 amp breaker?

For a given wire size, increasing the current increases voltage drop. A general rule of thumb (and code minimum) for residential wiring in the United States is to use no smaller than 12 AWG wire on a 20 A circuit. Originally Answered: What wire gauge is needed for a 20 amp?

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What does white wire connect to?

A white neutral wire usually connects to a silver-colored terminal or white wire lead. A green or bare ground wire almost always makes a ground connection—to a ground screw on a device, electrical box, or appliance case or to a green wire lead.

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Where can I find thick copper wire in my house?

Here are some of the best places to find and collect this highly sought-after material.
  • TVs and Monitors.
  • Most electronics have insulated wires inside the metal housing, including laptops, printers, radios, and DVD players.
  • Desktop towers are a great source for scrapped insulated copper wire.
  • Large Appliances.

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How many watts can 8 gauge wire handle?

A basic rule of thumb is this. For up to 500 watts RMS, 8 gauge is sufficient. In the 500 – 1000 watt RMS range, you want to run 4 gauge. From 1000 – 1500 watts RMS you should be running 2 gauge.

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Do electrical wires need to be stapled?

One of the key principles in electrical code is to never have energized ends of wires outside of a box. The staples/anchors prevent the wire from being tugged on in the future and pulling out of the box. Staples + box anchor is a double-insurance that you might as well do when the walls are open.

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How far down are electrical lines buried?

The minimum depth requirement of a direct burial cable is 24 inches, except when installed under a concrete slab with a minimum thickness of 2 inches. In this case, the cable can be installed at only 18 inches deep.