The electric boiler heating tube is the heart of the electric boiler, and its performance is directly related to the performance of the electric boiler. The electric heating tube is generally in the form of a tube, and is composed of a metal stainless steel tube, a nickel-chromium alloy electric heating wire, an extraction rod, a connecting seat and a magnesium oxide filler. Under normal circumstances, the electric heating tube has a service life of 10,000-30000 hours. The service life of the electric heating tube mainly depends on the material of the electric heating tube, the surface heat load and the user's operation management level. The electric heating tube is a nickel-chromium stainless steel tube with a surface heat load of 6-9 W/cm2. In addition, the rated electric power of the electric heating pipe is also a very important performance indicator. Under the rated working conditions, the absolute value of the electric power deviation shall not exceed 5% according to the national standard. The connection mode of the boiler electric heating pipe is generally three-phase, and is symmetrically connected into a star shape (Y) or a triangle (△). Divided into two or more groups according to the size of the capacity. The electric heating method of the boiler electric heating pipe is characterized in that the water in the boiler is not charged. However, when the electric heating element leaks or bursts, the water in the boiler is also charged, which is called leakage. In addition, due to the degree of insulation of the insulating and thermally conductive layer of the electric heating element, the electric heating tube also has a certain leakage current. According to national standards, the leakage current should be no more than 0.5mA. Therefore, leakage protection should be provided on the electrical lines.