I hope that someone on the forum may have a comment or two about this
subject... and can help John.

- Bill

-----Original Message-----
From: John Smith [mailto:[log in to unmask]]
Sent: Thursday, May 05, 2005 7:21 AM
To: 'Bill Brooks'
Subject: RE: Web site question

Thank you for your response Bill, I am trying find out at what voltage and
at what distance I need to be concerned about a static discharge from a
plastic surface. I have a silicon wafer processing tool and there is concern
about static discharge from the exterior plastic panels. I want to be able
to determine, the voltage vs.. distance safe point, i.e. (at 500v of charge
an arc will not jump at a greater distance than .5") I understand that the
type of material, the humidity and other factors make a difference, but
there must be some test data some where that points to some generalities.

Thanks again for your time bill

John

-----Original Message-----
From: Bill Brooks [mailto:[log in to unmask]]
Sent: Wednesday, May 04, 2005 11:03 PM
To: 'John Smith'
Subject: RE: Web site question

http://sprott.physics.wisc.edu/demobook/chapter4.htm

see table 4.2

The issue with predicting electrical arcing is in defining the environmental
conditions that contribute to the 'break over' voltage. The presence of dry
ionizing air, or ionic contamination on a surface can greatly increase the
distance at which break over will occur. Once the arc is established, it
ionizes an electrical path which is much lower in resistance that the
initial break over voltage required to jump across the electrodes and the
two points of potential can be moved much farther apart and they will still
conduct...
What are you trying to do?

Bill Brooks


-----Original Message-----
From: John Smith [mailto:[log in to unmask]]
Sent: Wednesday, May 04, 2005 2:09 PM
To: [log in to unmask]
Subject: Web site question

Is there a guideline that references how far a static charge will jump?
i.e. a 500v charge could be expected to jump or ark how far?

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