Everything You Need to Know about THHN Cables

THHN cable or wire is among the most used cables that supplies power in residential, commercial and in industrial places for external purposes. THHN simply stands for Thermoplastic High Heat resistant Nylon jacket. Its ability to withstand extreme temperatures makes it ideal for use in outdoor places with very high temperatures.

Its ability to remain unaltered by extreme heat makes it ideal for use when it comes to heat control systems and fire alarm systems. THHN cables are often used for AC power distribution at voltage rates of 100 volts to 600 volts.

Features:
• Aluminum or copper conductor
• Solid or stranded conductor
• PVC insulation
• Nylon jacketing
• 600 volts
• 75°C to 90°C
• 6 to 14 AWG
• Heat and moisture resistant
• Abrasion resistant
• Durable

Construction:
THHN cables come with either an aluminum or copper conductor. These could be stranded or solid and either single or multi conductors. The conductors are put together in such as way that they are flexible during installation and termination. This eases the installation process as well as the time used. It is the perfect material in places where durability is required.

Insulation:
There are many types of wire insulation but when it comes to THHN, PVC is most ideal. Poly Vinyl Chloride (PVC) enables the cable to be used for outdoor purposes in places with high temperatures because it is resistance to heat and temperatures. The PVC housing makes the conductor perform excellently without fears of it being affected by the elements.

Jacketing:
The insulation and conductors are protected by a nylon jacket. It provides mechanical protection to the cable in the sense that it provides resistance to oil, moisture and gasoline. As the cable is pulled in conduit during installation, it experiences abrasion. The nylon jacket and thermoplastic sheath offer excellent resistance against abrasion.

When compared to unjacketed cables, nylon jacketing allows the conduit to have more wires with similar current capacity. This is a great advantage to THHN wires especially when it comes to built in and under floor systems.

Specifications:
NEC has spelled out clear THHN wire specifications. THHN wires need to be oil resistant and UL listed gasoline. They ought to have a jacketing that is resistant to abrasion, gasoline, oil, moisture and gasoline. The conductors with 6 AWG to 14 AWG sizes will be marked as VW-1. The conductor is also supposed to be made of annealed copper. The insulation material should be resistant to heat and moisture.

Approval and certifications:
THHN wires have been approved and tested by various international bodies and found safe. The bodies include;
• UL
• RoHS
• ASTM

What is THWN wire?
A THWN cable is sometimes used in the place of THHN cables as THWN-2. THWN stands for Thermoplastic Heat and Water resistant nylon. These kinds of cables have single conductors. The nylon coating makes the cables resistant to flames, oils, moisture, gasoline and other chemicals.

THWN cables have similar specifications and certifications as those of THHN. They are used in changing power distribution systems ranging from 110 volts to 600 volts in North America. They are used in the following areas;

• Machine tools
• Controlled circuits
• Conduit
• General purpose wiring

THWN wires have 19 strands in their conductors that have a gauge size of 6 to 14 AWG. Some examples of THWN cables include;

• THWN wire 8 AWG 19
• THWN wire 14AWG 19
• THWN wire 6 WG 19
• THWN wire 10 AWG 19
• THWN wire 12 AWG 19

Most Common Types of THHN/ THWN-2 cables:

• 14 AWG THHN/ THWN-2 Copper Wire - This comprises of a concentric lay stranded copper conductor and a nylon coating. It is used in wiring PCs, radios, gaming frameworks, TVs, home theatres and speakers.

• 10 AWG THHN/THWN-2 Copper Wire - it consists of a concentric lay stranded copper conveyor and a nylon coating as well. The THHN wire is found in conduits and cable trays. In cable trays, it is used for branch circuits, services and feeders. It is used for commercial buildings and industrial applications as specified by NEC 2.

• 6 AWG THHN/ THWN-2 Copper Wire - This one also has a conveyor made of concentric lay stranded copper. It is coated with a nylon coating. It can be found in industrial and commercial set ups and is used for general electrical purposes.

• 12 AWG THHN/ THWN-2 Copper Wire - just like the others, it has a conveyor made of concentric lay stranded copper. It comes with a nylon jacketing because it is a THHN cable. This jacketing works to provide resistance from Sunlight, dryness and moisture. It is of little size and for this reason, it is used to interface the small circuits in different items including PCs.

• 8 AWG THHN/ THWN-2 Copper Wire - it is a medium breadth wire operating at 40 amps to 55 amps. Similarly, it is used for private general electrical wiring. It is also used in wiring home theater, in conduit and in video frameworks.

• Aluminum THHN
• Copper THHN
• Tray cable TC TC-ER shielded THHN PVC