Proper use of ESD / Static Dissipative / Conductive Mats

[Halcyon]

Apologies if this is a noob question; When using a mat on a surface (such as a table top), I understand ideally that the mat and the person should be connected to a grounding point to prevent static discharge damaging electronics. However are there situations where the same or similar protection can be offered without the use of a fixed ground point? i.e.: Connecting a wrist strap directly to the mat so that the mat and and equipment placed on top are at the same electrical potential.

[Siwastaja]

If all your devices under development live on that ESD mat, and every time you start working, you connect yourself to the mat first, then theoretically this will work: everything's on the same potential. But this is a very small island.

In reality, people move around, and equipment moves around. In a perfect setting, everything would be slightly conductive, and connected to the same reference - which, logically, will be the actual ground as in the soil around the building. So you want to make the "island" as large as possible.

By connecting your ESD mat to the mains protective earth, you are closer to that ideal, with the least amount of work, building materials such as concrete being very slightly conductive.

In a more professional setting, using more controlled conductivity in building materials - such as ESD floor tiling etc. - becomes important. They are still referenced to the actual earth, to maximize the "island" and remove places where large static discharges would occur.

[FreddieChopin]

By connecting your ESD mat to the mains protective earth, you are closer to that ideal, with the least amount of work, building materials such as concrete being very slightly conductive.

Be aware that you have a proper mains (TT) system and not TN-C or TN-C-S. In my old work electrican misconnected phase and ground and I had high impendance 230V on ESD mat in workshop (more like janitor closet but still had a soldering iron). Most devices are today in II class so earth fault is not major issue.