Electromagnetic induction and eddy current effect: When alternating current passes through a single-core cable, an alternating magnetic field is generated around the cable. If this cable passes through a steel pipe, since the steel pipe is a conductor, the alternating magnetic field will generate electromagnetic induction inside the steel pipe, and then eddy currents will be produced in the steel pipe. Eddy currents are generated by O movimento circular de elétrons livres em um tubo de aço sob a influência de um campo magnético . Este processo consome energia elétrica e faz com que o tubo de aço aqueça . se houver calor excessivo, pode causar problemas de segurança como incêndios .}
Magnetic fields with opposite current directions cancel each other out: If multiple cables in the same circuit (such as three phase lines and one neutral line in a three-phase four-wire system) are run through the pipe together, due to their opposite current directions, the generated magnetic fields will cancel each other out, and thus no significant eddy currents will be produced inside the steel pipe. However, since single-core cables have only one conductor, the O campo magnético que eles geram não podem ser cancelados por outros condutores, de modo que o efeito atual do redemoinho será mais óbvio .
