GROUNDED: Your PCB, EMC/EMI, and SI Nuggets

Failing to connect the shield of the cables to the chassis with a low-impedance, 360-degree connection.

Here’s the principle:

The chassis functions as a Faraday cage, keeping the electromagnetic fields generated by the device inside and blocking interference from the outside.

When you connect wires and cables, you create potential weak points in this shield.

To address this, the cable’s shield must act as a direct extension of the Faraday cage, maintaining coverage along the entire length of the cable.

Using a pigtail connection?

That’s where things go wrong.

It breaks the Faraday cage and opens the door to common-mode currents and EMI emissions, leading to test failures and real-world issues.

Is a 360-degree connection always possible?

Not always—but when it’s not, there are alternatives.

I go into more detail on this in my free EMC/EMI Design Online course:

fresuelectronics.com/courses

- Dario

P.S. Want to become an EMI Specialist?

Book my 1-on-1 private live EMC/EMI training here: fresuelectronics.com/training