Grounding Can Reduce EMI or RFI?


Thread Starter


I have a problem involving unstable base voltage on our metal detector. I strongly believe that it is caused by EMI or RFI as we sometimes use walkie talkies near it and there are several motors driving the conveyor.

I am advised to do some grounding to the equipment but what gauge wire to use and is it better to drive a new grounding rod into the ground or can I use the structure grounding?
use a new grounding rod, the structure grounding is full of EMI. I strongly recommend a net filter for your metal detector(solve the problem whith my appl)

greez booster

Wayne Shimanis


Your first step should be to make sure that your grounds are good. However, even with the best of grounds, ground transients can occur. With newer microprocessor based equipment as little as 0.4 volt transients in the ground can cause unstable operation of all types of equipment. If after checking your grounds, you still have problems, check out the IL-GTT ground transient terminator or the new Theon surge suppresor\EMI\RFI filter\ ground transient terminator products from Vortex Technologies, Inc.

Wayne Shimanis

Richard Meininger

Response: It is possible that the connections to "ground" may be a contributor. But, remember that the controls in an aircraft do not connect to earth. Here is a simple rule. Do not run separate ground connections from inside your control system to the outside. Always tie the different grounds together inside your control system and tie this to the case/system ground. Then tie a single connection to safety/power/earth ground connection.

The exposed metal/safety ground system would be better defined as the EMI reference ground and this is what you would tie your filters or surge protectors to.

Hope this helps.