The calculation and measurement results for power losses in a steel pipeline of cables have been presented. A selected circuit for the location of cable phases in the pipe (in collapse scheme) has been given. To consider the influence of currents in the pipe upon the electromagnetic field (a corresponding circuit is presented) the reflection method was used. A mathematical calculation tool, corresponding equations and relationships have been presented. Experimental and calculated dependencies between a power loss coefficient and currents in cables for a one-phase model are given. The magnetic parameters of pipe material have been measured experimentally. The specific conductance of metal of the tube has been measured by using a double sheet in a catted ring.