The primary difference between standard NM and underground feeder (UF) cable is in the cable construction. Standard NM cable contains wires that are wrapped with paper and a relatively loose plastic sheath. UF cable has wires that are completely encased in solid plastic.
You choices are typically 10, 12, or 14 gauge. The second number indicates the number of conductors. A 12-2 Romex will have a black(hot) and a white(neutral) wire as well as an unsheathed copper wire for ground. A 12-3 Romex will have a black(hot), red(hot), white(neutral), and bare copper.
Thereof, What use is NM cable suitable for?
Uses for Three Types of Non-Metallic Cable The standard NM cable used for interior residential wiring inside walls and floor and ceiling cavities is known as NM-B. This cable is approved for use in dry locations only; you will never see it used in outdoor locations or buried beneath the ground.
Also to know is, What does UF mean in wire? underground feeder
Subsequently, question is, What is NM TW & UF wire? Type UF is covered by heavy plastic sheathing. The cable is designed for placement in the ground without being encased in protective metal conduit. Type TW wire has a thin thermoplastic insulation. that provides the wire with some measure of. moisture resistance.
Also, What is the sheath of a cable?
Insulation and sheath are the components of a cable that protect the conductor. … The insulation isolates the flow of electricity, and the sheath wraps around the outside of the cable to protect the conductors inside.
What is TW wire mean?
Thermoplastic-insulated wire is rated 600 V and is designated as follows: TW — Indicates a single conductor having flame-retardant, moisture-resistant thermoplastic insulation. The wire is rated 60°C wet or dry.
What do the letters on wire mean?
Labels On Individual Wires Here’s what the letter mean: T: Thermoplastic, a heat-resistant plastic used on many types of wire. H: Heat-resistant up to 167 degrees F. HH: Heat-resistant up to 194 degrees F. W: Moisture-resistant; suitable for damp and wet environments.
Can UF cable be used above ground?
The use of UF cable on the exterior surface of buildings or structures is permitted by Sec. 225.10(18) and Sec. 334.10(3) of the NEC. If the cable is exposed to physical damage it must be protected in accordance with Sec.
How do you fix a cable sheath?
– Position the wraparound sleeve over the cable damage, joint or splice and close the metal channel.
– Apply heat using the heat shrink gas torch to shrink the sleeve onto the cable sheath and melt the adhesive liner.
What is the difference between sheathed and unsheathed cable?
The difference between a wire and a cable is that a wire is a single electricity conductor, it is just one single wire, whereas a cable is a group of many wires in one covering, sheathed or unsheathed. … Unsheathed cable is just the insulated conductor, essentially identical to one core of a sheathed cable.
Does UF wire need conduit?
UF cable can be direct-buried (without conduit) with a minimum of 24 inches of earth cover. … Wiring buried inside rigid metal (RMC) or intermediate metal (IMC) conduit must have at least 6 inches of earth cover; wiring in PVC conduit must have at least 18 inches of cover.
What is unsheathed cable?
Unsheathed cable is just the insulated conductor, essentially identical to one core of a sheathed cable. The wiring rules refers to unsheathed cable as ‘insulated cables (without sheath)’, but common unsheathed cable is known in the trade as building wire, or TPI (thermoplastic insulated) cable.
What does sheathed cable mean?
sheathed cable (plural sheathed cables) Electrical wire that has the insulated stands enclosed in a further sheath. Wire for the transmission of electricity or electronic signals, protected by an enclosing web of earthed wire mesh or metal foil to avoid electromagnetic interference from (or to) other signals.
Does UF wire need to be in conduit above ground?
Similarly, does UF wire need to be in conduit above ground? UF cable can be direct-buried (without conduit) with a minimum of 24 inches of earth cover.
What is the purpose of having the sheath insulation on cables?
Insulation and sheath are the components of a cable that protect the conductor. The insulation isolates the flow of electricity, and the sheath wraps around the outside of the cable to protect the conductors inside and enable electricity transmission.
How can NM cable be protected?
Nonmetallic-sheathed cable must be protected from physical damage by rigid metal conduit (RMC), intermediate metal conduit (IMC), Schedule 80 PVC conduit, Type RTRC-XW conduit, electrical metallic tubing (EMT), guard strips, or other means approved by the authority having jurisdiction (AHJ) [334.15(B)].
Can NM cable be exposed?
The National Electrical Code forbids the use of NM cable in situations where it is exposed in a manner where physical damage is possible.
Don’t forget to share this post 💖
References and Further Readings :