When transferring the PCB board to another area. Is it useful to wear a wrist strap that is not plugged into a ground point?
Answer: No. The wire of #antistatic wristband# must be grounded in order to effectively discharge the static charge to the ground.
ANSI/ESD S20.20 6.2.2.1 Requirements for grounding personnel, "When handling ESD sensitive items, all personnel shall be grounded or electrically connected to ground or artificial ground. When personnel are seated at ESD protected workstations, they shall Connect to common ground."
ESD TR 20.20 Section 5.2.3 Floor-Footwear System, Persons can also be grounded by using the floor and footwear system. This is useful when people are moving or standing in areas where wrist straps cannot be worn and ESDS items must be handled or transported. Maintain a path to ground by using dissipative or conductive floors and dissipative or conductive shoes. Flooring—A footwear system may be installed to provide an alternate personnel grounding system. When used as a primary personnel grounding system, the ground resistance including personnel, footwear, and floor must be as specified for wrist straps (< 35 x 10 6 ohms), or the voltage accumulation on the personnel must be less than 100 volts.