EMC Cables: Screened Power Cable for Variable Speed Drives

EMC cable is a flexible, braided-screened power cable purpose-built for connecting variable speed drives (VSDs) to motors. HELU Australia's range is manufactured to AS/NZS 5000.1 and available with either a full-size earth conductor or three split earth conductors, giving installers the flexibility to meet both personal safety earthing and the symmetrical, low-impedance earthing that VSD installations need for good electromagnetic compatibility.

Braided copper screening: Controls the high-frequency electromagnetic interference generated by VSD switching, protecting nearby equipment and signal cabling.
Full or split earth configurations: A full-size earth conductor for standard installations, or three split earth conductors symmetrically arranged around the cores for improved EMC performance.
Purpose-built for VSD connections: Sized and constructed specifically for the motor-side cabling of variable speed drive installations.
Flexible construction: Stranded conductors for easier routing and termination in drive cabinets and motor terminal boxes.
AS/NZS 5000.1 manufactured: Built to the same Australian low-voltage cable standard as HELU Australia's wider cable range.
Two sheath options: Clear sheath with full earth, or black sheath with split earth, to suit site identification and installation preferences.

EMC cable has flexible power conductors with a braided copper screen, which provides a low-impedance path to earth for the high-frequency interference generated by a VSD's pulse-width-modulated output. The split earth configuration arranges three reduced-section earth conductors symmetrically between the power cores, keeping the conductor layout balanced — a symmetrical arrangement helps prevent circulating currents being induced in the earth conductor, which is a key factor in achieving good electromagnetic compatibility. The braided screen must be terminated at both ends with a low-impedance, 360-degree connection to remain effective, rather than being left as a simple pigtail.

EMC cable is specified for the motor-side connection between a variable speed drive and the motor it controls, wherever electromagnetic interference needs to be contained rather than radiated into the surrounding installation. It's used across industrial and commercial sites running VSD-controlled pumps, fans, conveyors, and other motor-driven equipment, particularly where drives are installed near sensitive control, instrumentation, or communications cabling that could otherwise pick up interference.

Why do variable speed drives need screened cable? A VSD's pulse-width-modulated output generates high-frequency electrical noise that can radiate from unscreened cable and interfere with nearby equipment. A braided screen, correctly earthed at both ends, controls this interference and keeps the installation electromagnetically compatible with the equipment around it.

What's the difference between full earth and split earth EMC cable? Full earth cable has a single, full-size earth conductor. Split earth cable arranges three reduced-section earth conductors symmetrically around the power cores, which helps prevent circulating currents in the earth conductor and supports better EMC performance in VSD installations.

How should the cable screen be terminated? For the screen to remain effective, it needs to be terminated at both ends with a short, low-impedance connection — ideally a full 360-degree contact at the gland — rather than a long pigtail lead, which can introduce impedance and reduce shielding effectiveness.