ESD equipment grounding strap

[ADR_1]

Hello,

I have a controller (LCD, processor, PSU, with encoders and a joystick) in an aluminum enclosure that occasionally experiences malfunctions due to ESD events. Through some basic testing in the lab, I have found that connecting the enclosure to an earth ground using a 50cm long ground strap significantly improves the controller's resistance to malfunctions caused by ESD events.

I have tested using a 10AWG flat braided strap and a regular stranded insulated 10AWG hookup wire and did not observe any difference.

Is the braided ground strap or wire strap recommended?

I'm tending more towards the braided strap since with ESD events the rise time is on the order of nano seconds, which could result in the skin effect becoming significant, but I'm not sure.

Any direction or advice would be much appreciated. Thanks!

 

[rhaynes]

The problem is not lack of grounding since a lot of equipment is not grounded. The problem is with susceptibility of the circuit to high frequency RF. You need to add filtering to any wires leaving the board to prevent pickup. Without more circuit details I can't provide any suggestions.

If the grounding is acceptable then it will be the length not so much the width. The length will dominate the inductance. But I'm guessing that the ground won't fix it completely.

Ray

 

[ADR_1]

Thanks for your advice Ray. The grounding provides a huge improvement to the resistance to ESD events directly to the enclosure, but does not completely eliminate the malfunctions. I will look into filters on the wires as well.

Thanks.