Harmonic impedance of single-core armored cables

Single-core armored cables are frequently used for power distribution in large buildings. Because of the concern of safety, the armors of these cables are normally bonded and connected to earth. This, however, may create overheating problems or others when the cables carry rich harmonic currents. This paper presented an experimental investigation into harmonic resistance and reactance of the single-core armored cables. Harmonic impedance under different cable arrangements including the flat and touching, flat and spaced, and trefoil configurations were addressed. The impact of the method of armor bonding was studied via the experiment on 185 mm² single-core copper stranded cables. Finally recommendations on the installation of single-core armored cables are provided.