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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.
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