Fowler Associates Labs

Questions From Readers
Should The ESD Ground Be Close to the Lightning Arrester Ground Point?

This question was submitted by Nigel Goring:

"I have recently observed an electrostatic workstation grounded to a ground plate buried externally to the building within 20 feet of the building Lightning arrester ground.

I have been searching the web for guidelines/requirements with regard to the safe location of such grounds and any minimum distance requirements between such ground but have not been able to find any information.

Could you possible advise me if there are such requirements or point me in the right direction."

Does anyone have any suggestions?

E-mail your answers or suggestions

Response #1:

NFPA 77 is the standard for static electricity and NFPA 780 is the standard
for lightning protection systems, neither of these standards provide any
requirements prohibiting the two grounding electodes from being located
within 20 feet of each other. However, all grounding electrode systems, such
as electrical, telephone, CATV, ligntning protection, and static systems
must be bonded together, so that when a lightning strike occurs, all systems
will rise to the same potential, thereby minimizing the shock hazard and
side-flash.

Response #2:

It is the ESD Journal's opinion that this is a special case where people are tethered to the ground point. This means the ground plane rise during an event could make the wrist strap / workbenches elevated in potential and dangerous. We believe the ESD ground should not be so close or even attached to the lightning arrester ground. Help us out here with some logic.

Response # 3:

I think the ESD ground should not be so close or even attached to the lightning arrester ground. in our company,we also do that.And now,we just compile the ESD training book,please give us advice.