Today, we are continuing the great discussion of common wires used in electrical projects. This has been a long one, so if you have not already read our recent blogs on this topic, check them out. Continue on to read about more common wires including low voltage wires.


Like we previously stated, check out our recent blogs to get caught up on some of the other most common wires. THHN and THWN are codes for two of the most common types of insulated wire used inside conduit. Conduit is the protective tube that protects electric wiring.

THHN and THWN wires are unlike NM cable because they are single conductors. NM cable consists of two or more individual insulated conductors bundled up inside of plastic sheathing. This is just one way they are different.

Instead of being coated in NM cable sheathing, THHN THWN wires are protected by tubular metal or plastic conduit. Conduit is useful and commonly used in unfinished areas such as basements and garages. Often, they are found for short runs inside the home.

Two examples, the garbage disposal or hot water heaters. The letters indicate specific properties of the wire insulation. Let’s begin with THHN.

T- thermoplastic

H- heat resistant

HH- highly heat resistant

W- rated for wet location

N- nylon coated (for added protection)

Both THHN and THWN wires have colored sheathings. The colored sheathings are basically used to identify their function in a circuit. Hot wires are usually red, black, or orange.

Neutral wires are white or brown. While ground wires are green or yellow-green. THHN and THWN are are both circuit wires that should really never be handled when the circuits are on.

Low voltage wires:

Now, let’s dive into low voltage wires. For circuits requiring fifty volts or less, low voltage wiring is typically used. Places low voltage wiring includes:

  • landscape lighting wire
  • sprinkler system connections
  • doorbell wires
  • speaker system wires
  • thermostat wires

The size of low voltage wires range anywhere from twenty-two gauge to twelve gauge. Similar to lamp cord wire, low voltage wires are typically insulated. They may be contained in cable sheathing or combined twisted pairs.

This sort of wire can only be used in low voltage applications. Low voltage wires are typically small wires. They are much different from standard circuit wiring.

Although low voltage wires rarely cause serious shocks, it is still very important to always handle wires as if they can do serious harm to you. Always turn off devices before working with wires, or simply rely on experienced electricians from Sanford Electric Company to do the dangerous, important work of handling electrical wires.

Next week, we have a few more common types of wires to share with our readers. Be sure to stop by! Do not forget to call your trusted Sanford Electric electricians to inspect your home before family comes over for the Thanksgiving holiday.

Staff Writer

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