ESD safety — For a conductive ESD workbench/mat, what should it be grounded to for best practice in a typical office/service environment?

Introduction / Context:
Electrostatic discharge controls rely on a single common, safe reference point so charges bleed away slowly without creating hazardous shock risks. Proper grounding of mats and wrist straps is essential.

Given Data / Assumptions:

• Conductive/antistatic mat on a service bench with a 1 MΩ safety resistor in the ground lead.
• Standard building wiring with a verified safety ground in the AC outlet.
• Technician uses a wrist strap connected to the same reference.

Concept / Approach:

Best practice is to tie the ESD mat and wrist strap to the building’s AC safety ground. This provides a stable, low-impedance reference and ensures all equipment chassis connected to mains share the same ground potential, minimizing differential voltages.

Step-by-Step Solution:

Verification / Alternative check:

ESD standards and training materials specify connection to equipment grounding conductors, not to signal grounds or floating metal alone.

Why Other Options Are Wrong:

Bench-only ground leaves the system floating. Motherboard pins are not a safe tie-point. A chassis that is not tied to building ground can float and create ESD or shock hazards.

Common Pitfalls:

Bypassing the 1 MΩ resistor, using unverified outlets, or daisy-chaining grounds to random pipes or radiators.

Final Answer:

AC outlet safety ground.