Planning the electrical installation 37
Sufficient shield conductivity to suppress emissions
To effectively suppress radiated and conducted radio-frequency emissions, the cable
shield conductivity must be at least 1/10 of the phase conductor conductivity. The
requirements are easily met with a copper or aluminum shield. The minimum requirement
of the cable shield is shown below. It consists of a concentric layer of copper wires with an
open helix of copper tape or copper wire. The better and tighter the shield, the lower the
emission level.
Recommended AC output power cable types
The power cable types that can be used for the inverter AC output are represented below.
1 Insulation jacket
2 Copper wire screen
3 Helix of copper tape or copper wire
4 Inner insulation
5 Cable core
Symmetrical shielded cable with three phase conductors and a concentric PE
conductor as shield. The shield must meet the requirements of IEC 61439-1, see
above. Check with local / state / country electrical codes for allowance.
Symmetrical shielded cable with three phase conductors and a concentric PE
conductor as shield. A separate PE conductor is required if the shield does not
meet the requirements of IEC 61439-1, see above.
Symmetrical shielded cable with three phase conductors and symmetrically
constructed PE conductor, and a shield. The PE conductor must meet the
requirements of IEC 61439-1.
A four-conductor system (three phase conductors and a protective conductor on a
cable tray).
WARNING! Ground all conductive cable supports, cable clamps and
individual conductive items close to cables, such as cable trays.