Q & A With Britech Electric Cable Heating Systems

Q. I have a flat roof and my roof drains often freeze up in the winter, which results in damage to the roof. What can I do?

A. Install heating cable on the roof around the drains covering an area about a meter in diameter, drop some cable down the drains to where the drain pipe enters the heated area of the building. Should the roof drains go to an external downspout, install heating cable inside the downspout to the point of discharge and or below the frost line to prevent freezing and rupturing the downspout and drain lines.

Q. Why are my self-regulating cables still drawing power and heating up despite the heat wave we’re having?

A. Self-regulating heating cables never stop producing heat, they simply reduce the heat output according to the ambient temperature. Even on the hottest summer days these cables are warming the piping, often for no reason. In the case of heating cables on well lines and other domestic cold water lines when you hope to have a cold glass of water the water may be warm because the cables are still heating. Freeze-prevention pipe tracing cables are still warming the piping for no reason. Every heating cable should have a thermostat, and of course a GFI as required by code.

Q. I have a pipe tracing project in a food factory that requires different types of piping and different types of products in the pipe that need to be kept warm or hot. What should I be wary of?

A. Most of the piping in the plant will be stainless. Use the correct pipe fastening tape for the heating cable so that it won’t harm the stainless steel. You may also require thermostats that can control the temperature (i.e., setpoint) in a very narrow band to ensure the liquid is neither too hot nor too cold. Thermostats that control only minimum or maximum temperatures are not acceptable for this purpose.

Q. I’ve meagered out the self-regulating cable and it is clear, but the breaker keeps tripping.

A. Often the cable lengths can be too long and place too high a load on the breaker. Load and length charts from the manufacturer should always be consulted when sizing circuits. For instance, the manufacturer's chart for a 5 watt per foot cable installed on a 20-amp208-volt circuit may only allow for a 375-foot-long length of cable. If the cable exceeds the 374 feet it will trip the breaker.

Q. How do I make sure that the approvals for electrical equipment certified for Canada are accurate? 

A. Heating cables, radiant panels and heating cable sets should be certified according to CSA Standard CSA-130.22.2 or later. We get many inquiries about offshore products that bear an approval that are not for use in Canada or have been approved under the wrong standard. Should there be a fire or injury, I doubt if your electrical safety regulator or your insurance company will accept that “You thought it was okay” because there is a stamp or label on the products. We would be pleased to discuss any floor warming, snow melting, pipe tracing or roof de-icing products with you.    


Q. Do I need to insulate pipes after installing heat tracing cables?

A. Considering the extreme temperatures of the Canadian climate, all traced pipes should be insulated. Pipe trace cables are only secured to a very small cross section of the pipe and in extreme cold would not supply sufficient heat to keep the pipe from freezing. Pipe tracing charts specify the amount of heat required according to the pipe diameter and the thickness of insulation required, as well as the ambient temperature of the area where the pipe is installed.

Q. How many heating cables can I install on a thermostat?

A. I asked two highly regarded consultants about this one and consulted Section 62 of the electrical code. Both consultants agree that hiding heating cables under combustible materials was a very bad idea. They could overheat or be damaged by personnel traffic or equipment being rolled over the roof. Section 62 of the code says, “The heating portion of heating cable sets and heating panel sets shall not penetrate or pass through walls, partitions, floors or similar structures.”

Q.We are involved in a high-profile project where the architect is demanding that the roof de-icing cables be hidden under the roofing material. What’s your opinion?

A. I asked two highly regarded consultants about this one and consulted Section 62 of the electrical code. Both consultants agree that hiding heating cables under combustible materials was a very bad idea. They could overheat or be damaged by personnel traffic or equipment being rolled over the roof. Section 62 of the code says, “The heating portion of heating cable sets and heating panel sets shall not penetrate or pass through walls, partitions, floors or similar structures.”

Q.My boss has asked me to monitor our heat tracing cables to determine the amount of power they use for freeze prevention and process requirements. How can I do this?

A. I suspect this is an industrial application and you may have multiple systems operating under various applications. Heat tracing controllers that monitor power usage and control each circuit are available. These are sophisticated controls that monitor GFCI trip, high temperature, low temperature, RTD failure, loss of power, and loss of conductivity. They can be connected directly to the building’s operations centre through an RS 485 port for monitoring and control. They also should have a current monitoring function for each circuit to determine power usage and possibly help to determine whether tthe proper cable has been installed on the pipe or tank. We have found many instances where cut in the field, constant wattage cables are a better application than self-regulating cables for long life, energy saving and reduced hydro demand charges.

Q. We are installing a pipe trace system on plastic piping in an underground parking garage. What concerns should I be aware of?

A. First of all you need to be aware of Section 62-308 of the Canadian Electrical Code. Heating cables on non-metallic pipes require a thermostat on each pipe. “A heating cable set or heating panel set installed on a non-metallic pipe, duct, or vessel shall be controlled by a thermostat or other suitable temperature-limiting system so that it does not cause damage to the pipe, duct, or vessel.” Using one ambient air sensing thermostat to control all of the pipe tracing on separate non-metallic pipes does not meet the letter of the code.

Q. What precautions should be taken when sizing heating cables on non-metallic piping?

A. Pipe tracing on non-metallic pipes such as PVC, PEX or CPVC that are used for water supply, waste and storms piping should be sized according to the diameter of the pipe, the lowest ambient temperature it will operate at and the amount of insulation installed to keep it from freezing. Heating cables on plastic pipes should never exceed 5 watts per foot (15 watts per meter) to avoid damaging these pipes due to excessive heat from the cable. On larger pipes where you may need in excess of 5 watts per foot install two or more runs of heating cable. The cables should have one run of aluminum high temperature tape installed directly on the pipe and then the cable is attached with another layer of tape over the cable and the first layer of aluminum tape. This aids in heat distribution. Pipe tracing charts are available from Britech. You can reach us at www.britech.ca and we will send you a catalogue.

Q. We recently had a fire hose cabinet valve freeze in our underground parking garage yet, when the pipe trace system was tested it performed perfectly. What could be the cause?

A. We often see the pipe tracing temperature sensors installed on the piping near the thermostat that is located in an electrical room, often in the warmest part of the garage. Temperature sensors should be extended and installed near the roll up garage door or near the intake air louvres where they can sense outdoor air temperatures rather than the warm air in the garage. A frozen fire hose cabinet will be useless if it’s frozen and unable to supply water in case of a fire.

Q. The line to my septic tank froze last winter. Can I install a heating cable inside the pipe?

A. There are heating cables made to be installed inside some pipes, though installing a heating cable in a septic line could be very dangerous due to the explosive gases in the pipes, tank and septic bed. Areas in sewage treatment plants where gases may accumulate are considered, as a minimum, to be Class 1 Div. 11 areas, meaning they are a hazardous area. Rather than have your house explode, install a heating cable on the outside of the pipe and insulate it to prevent this happening again.

Q. I have a flat roof and my roof drains often freeze up in the winter, which results in damage to the roof. What can I do?

A. Install heating cable on the roof around the drains covering an area about a meter in diameter, drop some cable down the drains to where the drain pipe enters the heated area of the building. Should the roof drains go to an external downspout install heating cable inside the downspout to the point of discharge and or below the frost line to prevent freezing and rupturing the downspout and drain lines.

Q. I just received a heating cable on a spool and tested it. It didn’t megger well. It seems faulty. What should I do?

A. Heating cables are factory tested and quality manufacturers do not normally ship unsatisfactory product. When the cable is spooled at the factory or the electrical distributors warehouse the cable is cut to length but it is not capped with an end seal in the manner prescribed by the manufacturer for an installation. It may only have a temporary cap to keep moisture out. When the megger test is done, normally at 1000 or 2500 volts the current can short at the end of the cable on the spool and display a fault reading over 20 megohm.