Question: Do I Need to Ground an ESD Mat That is Sitting On A ESD Floor?
Answer: No. But Only If Your Mat Passes a Resistance to Ground Test
In many cases an ESD mat that is sitting on an ESD floor does not need to be hard grounded. However, you need to measure the mats resistance-to-ground (RTG) to make sure that it is < 1.0 x 109 ohm when sitting on the ESD floor. Testing is a required step for all ESD programs and is important step in this ESD mat/floor setup.
Adding ESD mats to an area with an ESD floor is a great idea, especially ESD anti-fatigue mats for standing personnel or ESD chair mats to protect the floor from wear and tear from wheels. Because ESD mats have dissipative properties, static can flow from the mat and continue through the ESD floor to ground. If your set up passes your RTG test, there is no need to add a ground wire to the ESD mats.
If you need to test your floors, the Metriso 3000 resistance test kit is an excellent tool for the job.
