50’ Pipe Freeze Protection Self-Regulating Heating Cable, 10W/ft., 240V

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.

Yes, it can be used for both application types to prevent pipes from freezing and bursting during cold weather.

No. They are not designed to be powered by DC voltage. They must be used with AC voltage. 

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.

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.

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.

WarmlyYours does not recommend using an extension cord for permanent installations. Pipe heat should always be plugged directly into a receptacle or hardwired to the circuit that is powering it.

No.  It is not listed for this application, and it is not warrantied for use in direct burial or wet applications.

No. Only install pipe heat (heat trace cable) in accessible locations. Do not install this self regulating cable in walls or any place where the cable is hidden. Do not run it through walls, ceilings, or floors. The cable must be installed 10“ away from combustible surfaces, such as wood, and it should not be embedded in insulation or roofing material.

Do not wrap self regulating cable around the pipe in a coiled or spiral fashion, and do not use electric tape to attach it. WarmlyYours recommends attaching the cable in a straight run and to use aluminum or fiberglass tape, pipe straps, or plastic zip ties to attach the cable. Then cover the assembly with fire-resistant insulation and assure it is waterproof. Place electrical heating cable WARNING labels every 10‘, and where the label will be clearly visible.