Simply put, yes--the right type of heat tape will really keep your pipes from freezing. By applying gentle heat, heat tape can prevent the water in your pipes from turning to ice and blocking the flow of water--or worse. Combined with proper insulation, heat tape regulates the overall temperature of your water pipes.
Heat trace, heat tape, or heating cable for pipes is typically an electric heating cable that can be attached to the pipe which helps keep non-flowing water pipes in poorly insulated perimeter walls flowing despite harsh winter temperatures.
No, as long as it's properly installed. However, improper installation, use, and/or maintenance of electrical heating cable can cause fires, electric shock, and/ or frozen pipes.
By attaching a heating cable to the exterior of a pipe, it will transfer the heat to the pipe to prevent frozen pipes. And with the use of pipe insulation the heat will be evenly spread and won't dissipate as quickly.
Unfortunately there's no set answer for this because it depends on many factors such as the diameter of the pipes, the installation density of the heating cables, the outdoor temperature, the installation of thermal insulation sleeves, etc.
There are too many variables to provide an accurate answer. Even though this product is designed to keep pipes from freezing, it is not designed to thaw pipes. If your pipe has frozen with the heat tape installed and energized, please check the placement of the built-in thermostat and verify that the insulation has been properly installed and waterproofed.