Waterproof Wire: Suitable for Wet Conditions


As we know, an electric wire comprises a solid or stranded conductor. And the conductor is either bare ( copper grounding wire) or may have insulation. Generally speaking, the insulation decides which condition a conductor is suitable for. Usually, wires that can withstand damp conditions can also work in dry conditions; however, wires meant for dry conditions are not necessarily ideal for wet conditions. Today, we will have a clear picture of the waterproof wire.

Table of Contents

Whether your Wire Waterproof or Not?

Usually, waterproof wires are used in outdoor appliances. And you can identify the insulation of a wire through a code that includes letters and numbers. 

Wire coding:

If you want a wire for wet conditions, the best way is to look for W in the wire code. “W” stands for damp. However, some cables do not include “W” in their code but are still ideal for damp locations. Below is a list of some code letters used in the wire meant for residential applications:

  • T: thermoplastic; refers to the type of plastic insulation
  • X: thermoset; plastic used for insulation
  • H: heat-resistant; if HH, it means higher heat resistance
  • N: nylon-jacketed; insulation comprises a coating of nylon for added protection
  • W: wet locations

The standard residential wires are THHN and THWN. 

On the one hand, THHN refers to thermoplastic, high heat resistant, and nylon jacketed wire. And it will not sustain wet conditions as there is no “W.” On the other hand, the THWN wire is a thermoplastic wire and can work in wet conditions.

In addition, the application of a wire can affect temperature rating. For example, THHW wire has a temperature rating of 90 degrees Celsius, but for wet locations, its temperature rating is 75 degrees Celsius. 

Shortlist of waterproof wires:

Some wires do not have “w” in code names but can work in wet locations. Also, you may notice a higher value of one or more ratings. For example, THWN has 75 degrees Celsius in dry and wet conditions, whereas THWN-2 has a higher temperature rating (up to 90 degrees Celsius) for dry and damp locations.

  • SHOW
  • THW
  • THW-2
  • THEN
  • THWN-2
  • XHHW
  • XHHW-2
  • IF
  • USE
  • USE-2

What are waterproof cables?

A waterproof cable, water block cable, watertight cable, or water-resistant cable is a multiconductor cable suitable for wet or aquatic locations. 

Some of the features of these cables are:

First, they can survive in submerged environments and function correctly at different lengths.

Secondly,  they have a unique outer jacket made of material that can work in wet conditions. 

Finally, they use water-blocking fillers or water-blocking tape to ensure proper functioning.

outdoor waterproof insulated wire, cable, internet, gas cord, and metal-plastic tap system

Image: outdoor waterproof insulated wire, cable, internet, gas cord, and metal-plastic tap system

Water-Resistant Cable Applications

  • Fire Alarm Systems
  • Military
  • Pressure sensor equipment
  • Oil & Gas Refineries
  • Conveyors and forklifts
  • Industrial PCs
  • Outdoor TVs and direct bury applications
  • Audio-Visual Equipment
  • GPS
  • Marine communications

Water-resistant materials for cables

  • Water blocking tape: These are swellable tapes wrapped around the cables. Thus, the water does not penetrate deep into the cables.  
  • Water blocking gel: It is a soft, hydrophobic, gelatinous substance that protects cables from moisture and even water standing.
  • Water blocking fillers: Fillers are materials filled in the cable’s hollow areas to prevent any leakage if a tear occurs in the outer jacket.

As a result of these waterproofing materials, cables can handle different amounts of moisture depending on their complete construction.

Shortlist of waterproof cables:

Submersible cable:

You can submerge these cables in a liquid, as evident by the name.  Also, you can use it as a direct-buried cable. These cables have very rugged insulation, which is durable and abrasion-resistant. Generally speaking, they are available in single or multi-conductor forms in flat or round shapes, depending on the application requirements. And the conductors are available in different colors that help you differentiate between earth and phase connections.

These cables supply power to underwater pumps and submersible motors for mining, agriculture, or drilling purposes. Thus, these are the sturdiest cables that allow your electrical appliances to work efficiently. 

cables with submerged pumps color icon vector illustration

Image: cables with submerged pumps color icon vector illustration

Underground feeder cable:

These underground cables are suitable for supplying power to street lights and lamp posts. And they are non-metallic conductors with an outer layer of thermoplastic material to resist moisture and fungus. Unlike submersible cables which need rugged insulation, you can bury these cables directly under the ground with or without conduit. 

Image: cable drum with underground cables

Image: cable drum with underground cables

Direct buried cables are best for communication and power transmission. They have a waterproof layer, shock-absorbing gel layer, or plastic layer to protect against moisture, heat, and other underground factors. There is no need for conduits; these cables are easier and cheaper to lay. However, during excavations and digging, these cables get easily cut. Thus, you will mainly find them on side roads. 

Flexible, portable cord:

Also known as the service cord, these cables are multiconductor cables that you can use for electric power connections that require flexibility. Indoor and outdoor wiring industrial pieces, such as machinery, heavy-duty tools, large appliances, and lightning construction sites.

Commonly used UL and CSA designations for flexible cable power cords include:

Common types of service cord

  • SOOW and SJOOW 

Firstly, a thermoset rubber jacket is resistant to melting in momentary contact with a hot surface.

Secondly, abrasion resistance.

Thirdly, low cost.


Firstly, a thermoplastic elastomer jacket.

Secondly, a wider continuous temperature range.

Thirdly, better flexibility at very low temperatures.


Whether your application has moisture, has flowing water in its surroundings, or is wholly submerged, waterproof wires and cables can help. Although they have varied constructions and different customizable options available, technical experts from Cloom help you with the best solutions for your applications.