What heat tracing is
Heat tracing is an electric heating cable that runs along a pipe, drain, gutter or tank to replace the heat that escapes in cold weather. It does not heat the space around it. Its job is to keep one thing just warm enough to stay liquid, or to keep snow and ice from building up.
In Edmonton, where frost goes deep and cold snaps can sit at -30 C for days, heat tracing protects water lines in crawl spaces and unheated garages, keeps roof drains flowing, stops sprinkler lines from freezing and keeps industrial process lines at temperature.
Heat tracing is sometimes called heat tape, heat cable or trace heating. The cheap plug-in tape sold for one pipe is a small cousin of the engineered systems used in commercial and industrial buildings, but the same principles apply.
How it works on a pipe
The cable is fastened along the pipe, usually on the lower side, with tape or ties. Aluminium tape is often used on plastic pipe to spread the heat. Then the pipe and cable are covered with thermal insulation and a weather jacket.
The insulation is just as important as the cable. Heat trace is sized to make up the heat lost through the insulation. Without insulation, or with soaked or crushed insulation, even a good cable cannot keep up on a cold, windy night.
Designers work out the heat loss from the pipe size, insulation thickness, the lowest expected air temperature and the temperature the pipe must hold. That number decides the cable output and whether one run or two is needed.
The parts of a proper system
A heat trace system is more than a cable plugged into a wall. A complete installation includes:
- Circuit protection with ground-fault protection. The Canadian Electrical Code requires ground-fault protection on heating cable circuits, because a damaged cable can leak current without tripping a regular breaker.
- Control. A thermostat or controller turns the cable on only when it is needed, based on air or pipe temperature. Larger systems use controllers with alarms and monitoring.
- Power connection and end seal kits that match the cable type. Homemade splices and taped ends fail.
- Labels on the insulation showing the line is electrically traced, so nobody cuts into it unaware.
- Insulation and jacket sized and sealed for the location.
Types of heating cable
There are three main families of cable, and each suits different jobs:
| Cable type | How it behaves | Typical use |
|---|---|---|
| Self-regulating | Output drops as the cable warms up | Water lines, roofs and gutters, most freeze protection |
| Constant wattage | Same output along its length no matter the temperature | Long runs, some process lines |
| Mineral insulated (MI) | Metal-sheathed, handles very high temperatures | Industrial process and high-temperature work |
Within each family there are different output ratings, jacket materials and temperature ratings. A cable with a basic jacket might be fine in a crawl space but not where it is exposed to sunlight, oils or chemicals. Roof and gutter cable has its own listings for that use. Matching the cable to the job, and to the pipe material, is the first design decision.
Controls matter too. A simple ambient thermostat turns the cable on below a set air temperature. A pipe-sensing controller watches the pipe itself, which saves energy on lines that stay warm from flow. Roof systems often use snow and moisture sensors so the cable only runs when there is something to melt.
Our guide to self-regulating vs constant wattage cable goes deeper on the choice.
Why installation matters
Most heat trace failures we see in Edmonton come from installation and maintenance problems, not bad cable. Common causes include:
- Cable installed with no ground-fault protection, or protection that was bypassed after nuisance trips.
- Plug-in cable left on all year with no thermostat, wearing out early.
- Wet or missing insulation, so the cable cannot keep up.
- The wrong cable for the pipe, such as a product not rated for plastic pipe.
- Damage from later renovations, where a trade cut or crushed the cable.
Some cable types must never cross themselves or be covered by anything other than the specified insulation. Follow the manufacturer's instructions and have a licensed electrician install permanent systems.
Start-up load is another trap. Self-regulating cable draws much more current when it is first switched on cold than it does once it warms up. A breaker sized for the running current alone may trip every time the system starts on a frigid morning. Circuit sizing should follow the manufacturer's start-up figures at the lowest expected temperature.
Permanent heat trace circuits need an electrical permit. In Edmonton that is issued by the City of Edmonton, and elsewhere in Alberta under the Safety Codes Act.
Keeping a system healthy
Heat trace sits idle all summer and then has to work every night in January. A fall check catches problems before the first hard freeze. For commercial and industrial owners, that check usually includes insulation resistance testing, controller and alarm testing, and a walk-down of insulation and labels.
Write down when each circuit was installed, its length and cable type, and what it protects. A simple list taped inside the panel door or kept with your home records saves time when something goes wrong at 2 AM.
Homeowners can do the safe part: test the GFCI or ground-fault breaker, make sure the indicator light on the thermostat or plug works, and look for torn insulation or damaged cable. Leave anything beyond that to an electrician.
If you have heat trace on critical lines, our heat trace maintenance service can set up a yearly fall inspection and written report.
Common questions
Is heat tracing expensive to run?
It depends on cable output, length, insulation and how the system is controlled. A good thermostat or controller makes the biggest difference, since the cable only runs when there is a real freeze risk.
Can I install heat tape myself?
Small listed plug-in kits are sold for homeowners, but permanent, hard-wired heat trace needs a licensed electrician and a permit. Either way it must have ground-fault protection.
Does heat trace work on plastic pipe?
Yes, if the cable is rated for plastic pipe. It is usually installed with aluminium tape to spread the heat. Check the product listing before buying.
How long does heat trace last?
Well-installed and controlled systems can last many years. Cable left on constantly, or with damaged insulation, wears out much faster. An annual check helps it last.
Codes and permit rules change and every building is different. For work on your system, talk to a licensed electrician and your local permit authority.