Previous in Forum: ad7710   Next in Forum: Electronic thermal managment
Close
Close
Close
5 comments
Rate Comments: Nested
Anonymous Poster

Static Bleed off Requirements

02/13/2008 9:54 AM

Gentlemen and Ladies,

I have a semi conductive material that has resistance between from 500,000 to 1,000,000 ohm-cm and needs to be protected from static electricity .What and how much of a conductive layer do I need to bleed off staic? I am more interested in a standard requirement specification that specifies Conductivity VS Static Barrier conductivity

Vince

Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#1

Re: Static Bleed off Requirements

02/13/2008 10:01 AM

Just earth it onto something. As far as static charge is concerned, it's a v.good conductor.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru
United Kingdom - Member - Olde Member!! Engineering Fields - Instrumentation Engineering - New Member

Join Date: Jul 2006
Location: Dunstable, England
Posts: 2821
Good Answers: 45
#2

Re: Static Bleed off Requirements

02/13/2008 11:27 AM

Wrap it up in aluminium foil (cooking foil) that will keep it nice bright and shiney as well as static safe

John

__________________
A little knowledge is a dangerous thing - Googling is far worse!
Reply
Power-User
Engineering Fields - Electrical Engineering - New Member

Join Date: Aug 2007
Location: Toronto
Posts: 239
Good Answers: 9
#3

Re: Static Bleed off Requirements

02/13/2008 10:48 PM

UL1203 - (Equipment for use in Hazardous Locations) states that:

33.4 Test for accumulation of static electricity
33.4.1 General
33.4.1.1 A nonmetallic external part with an area greater than 15.5 inch2 (100 cm2) shall comply with either the requirements in 33.4.2 or 33.4.3.
33.4.2 Method A
33.4.2.1 Any non-metallic surface with area greater than 15.5 inch2 (100 cm2) shall have a surface resistivity of 1 G-ohm or less at 23°C (73°F) and 50 percent relative humidity as defined by the material specifications or as determined by the test in 33.4.2.2.

33.4.2.2 The resistance is to be tested on the enclosure or on parts of the enclosure. Two parallel electrodes 0.04 inch (1 mm) in width, 4 inches (100 mm) in length, 0.4 inch (10 mm) apart are to be centered on a 6 by 2.4 inch (150 mm by 60 mm) sample. The sample is to be cleaned with distilled water, then with isopropyl alcohol, then once more with distilled water before being dried. Untouched by bare
hands, it is to be conditioned for 24 hours at 23°C (73°F) and 50 percent relative humidity. The test is to be carried out under the same conditions. A direct voltage of 500 ±10 Vdc is to be applied for one minute. The resistance is the quotient of the direct voltage applied at the electrodes to the total current flowing between them when the direct voltage has been applied for one minute.

Hope this helps

Reply
Anonymous Poster
#5
In reply to #3

Re: Static Bleed off Requirements

02/15/2008 8:53 AM

This is the best reply I received so far. Thanks a million.

Reply
Anonymous Poster
#4

Re: Static Bleed off Requirements

02/14/2008 7:32 PM

Work shoes have a static dissipation requirement, with upper and lower values.

With high humidity static charges build slow and drain rapidly.

With low humidity static charges build faster and drain slowly.

If you are wearing silk underwear you can build enormous static charges that will require a superconductor to drain!

Reply
Reply to Forum Thread 5 comments
Copy to Clipboard

Users who posted comments:

Anonymous Poster (2); Electroman (1); Graebeard (1); PWSlack (1)

Previous in Forum: ad7710   Next in Forum: Electronic thermal managment

Advertisement