Plugging An Overlooked Gap in EMI Defenses

Engineers who design for electromagnetic compatibility (EMC) long ago learned how to to manage EMI through the use of shielded electrical cabinets and high-quality cables with braided shields. But there’s a gap in EMI defenses that even experience engineers often fail to notice.

You can find that gap wherever cables enter control cabinets. Oftentimes, the cable connectors at this entry point fail to provide sufficient contact with both the cable shield and the metal cabinet walls.

Fortunately, this gap is easily closed by picking the right cable connectors. These connectors tend to have:

•      Low Impedance. To minimize cable shield impedance, the connector contact surfaces

should be as large as possible. Under ideal conditions, the cable shield should function as a continuation of the housing.

•      Low Induction. Minimized induction occurs when the cable shielding routes to the housing wall via the shortest possible path and with the widest possible cross-section.

•      Full Contact. The best cable connectors will also maintain contact with the shielding around the entire circumference of the cable to ensure there are no discontinuities between shielding and housing once the connection is made.

An example of a cable connector that delivers these characteristics is our new EPIC ULTRA model. It has been designed to improve EMI protection in the crucial juncture between the cable shielding and the control cabinet.

Unlike previous connector models that used finger-like springs to engage the cable shield, EPIC ULTRA features an integrated brush-style EMC fitting. The brush, combined with the nickel-plated housing, creates a conductive shell that functions like a Faraday cage and allows the connector to block external electrical interference.

Even at high frequencies, the brush-style connectors have low impedance and correspondingly high attenuation values. These values suggest that the brush-style grounding integrated in EPIC ULTRA can ensure that EMI defenses are intact from cable to cabinet.

For a more detailed look at our EMI resistant cable connectors and our impedance testing results, download our latest white paper.