Winter Heat Cables for Preventing Frozen Water Pipes

93% of fires caused by product overheating or short circuits

With recent cold waves hitting during the winter season, accidents involving frozen and burst water pipes are on the rise. To prevent such damage, many households use heat cables (freeze-prevention cables) installed outside their homes. However, fire accidents related to these cables are also increasing, requiring consumers to exercise extra caution.

A fire broke out in the water meter box of Mr. Lim’s corridor-style apartment in Songtan, Gyeonggi Province. He had wrapped the freeze-prevention heat cable multiple times around the water meter, and this overlapping section is suspected to have overheated, causing the fire. As seen in this case, frozen pipes and water meters installed outside homes often become a problem when winter cold snaps begin.

Many households use freeze-prevention heat cables to avoid such accidents, but fires caused by these products continue to occur. These cables—also called “pipe freeze-prevention heaters” or “anti-freeze cables”—are widely available on the market. They are powered through a connected outlet and prevent freezing by generating heat when wrapped around water pipes or meter boxes.

Frequent Fire Accidents in Single-Family and Multi-Family Homes

According to the National Fire Data System (NFDS) and the Korea Consumer Agency’s Consumer Injury Surveillance System, fires related to freeze-prevention heat cables are reported every year.

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The causes of fire were identified as:

Overheating: 56.1% (32 cases)
Short circuits: 36.9% (21 cases)
Electrical leakage: 7.0% (4 cases)

In most cases, the fire spread when Styrofoam or cloth insulation near the cable caught fire.

Fire locations were mainly:

Single-family and multi-family homes: 54.4% (31 cases)
Commercial buildings: 31.6% (18 cases)
Old apartment buildings: 7.0% (4 cases)
Farmhouses and livestock facilities: 7.0% (4 cases)

These fires usually occurred in outdoor locations such as water meter boxes, exposed water pipes, and water tanks..

Although freeze-prevention heat cable fires occurred most often in the winter during severe cold spells (59.6%, 34 cases), they were also reported in spring (26.3%, 15 cases), summer (8.8%, 5 cases), and autumn (5.3%, 3 cases)—seasons unrelated to freezing.
This is likely because many users fail to unplug the cables after winter ends. When surrounding temperatures rise and heat cannot escape due to insulation, the cable overheats and may catch fire.

Since January 2010, freeze-prevention cables have been required to carry Electrical Safety Certification (voluntary safety confirmation). However, many products still sold on the market lack this certification, indicating that stricter monitoring is needed.

How to Prevent Fire Accidents

Avoid overlapping the heat cable when wrapping it, as this can cause overheating. Make sure the plug area is not sharply bent or pulled with excessive force.
Avoid covering the cable with insulation whenever possible. Many households use insulation over the heat cable, but sparks from a short circuit or leakage can ignite the insulation and cause a fire. If insulation must be used, choose heat-resistant materials.
Do not bend the heat cable sharply. Silicone-type heat cables are soft and easy to install, but repeated stress on a bent section can cause cracking. When snow or rain enters the cracked area, sparks may occur and lead to fire.
Always unplug the cable when temperatures stay above freezing. If the surrounding temperature rises and trapped heat cannot escape because of insulation, the cable may overheat and ignite.