# Is it necessary to have insulator sheets between PCBs and antistatic mats?

I am recommended to use some insulator or paper sheets when testing PCBs on antistatic mat connected to ground via antistatic wrist band. Is this correct way. Why is it necessary to have insulator sheets in between?

• Sounds like some makeshift setup to get rid of the leakage. Either use an antistatic mat or don't, but isolators defeat the purpose of them. Sheets of paper are banned in all the ESD safe areas of my company for example. – Mister Mystère Mar 13 '15 at 15:37
• I would not generally permit the circuit board conductors and components to casually touch the work surface whether it's allegedly insulating, conducting or slightly conducting. You'll perhaps get the most dramatic results from a metal workbench and 'hot' mains-powered circuits, but more subtle troubles can occur with slight conductivity. – Spehro Pefhany Mar 13 '15 at 16:04

A decent quality rubber antistatic mat will have a low end top surface conductivity of $10M \Omega$. Working with an audio circuit where the highest impedance is a $100k\Omega$? You'll never have a problem. Working with a $10M\Omega$ pH sensor? Leakage will cause you problems. This is a question that needs to be answered on a project by project basis, based off the circuit and antistatic mat.