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Deal of the Week – 20% Off Surface Resistance Meter Kits!
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Discover deep discounts on high quality Charleswater ESD Control Products.
Save on your regular stocking orders.
20% Off Surface Resistance Meter Kit
99105 – Surface Resistance Meter Kit
99106 – Surface Resistance Meter
99108 – Leads for Surface Resistance Meter, Pair
99109 – Electrodes for Surface Resitance Meter, Pair
- Digital Compliance Verification Surface Resistance Meter Kit
Measures resistance point-to-point (Rp-p) or surface to ground (Rg) of working surfaces, flooring, garments, packaging, and other materials in accordance with EN 61340-5-1 per IEC 61340-2-3 - Meter measures ambient temperature and relative humidity
Available when required for test records - Colour coded LED and digital LCD read-out
Easy to read, no interpretation needed; can easily be used for quick go/no go checks - Made in the United States of America
Use code C101 at checkout. Valid for online orders only.
New Limit Comparator for Testers Available at Charleswater.co.uk!
Use to perform periodic calibration testing of the:
Dual Independent Footwear Tester
Dual Independent Footwear and Wrist Strap Tester
SmartLog V4™
SmartLog V5™
Frequency of recalibration should be based on the critical nature of those ESD sensitive items handled and the risk of failure for the ESD protective equipment and materials. In general, Charleswater recommends that calibration be performed annually.
Item | Description | Price |
50424 | Limit Comparator for Testers | $224.10 |
Resistors in Charleswater Mat Ground Cords
Using a current limiting resistor in the ground cord is the user’s choice; however, the resistor is not for ESD control purposes. Either without resistor or with a one megohm resistor is acceptable, but most all Charleswater ground cords do contain a resistor at the snap end.
Here is advice from our industry’s standard:
“An easily accessible dedicated EBP [EPA ground bonding point] for the wrist strap shall be established adjacent to each working area, or working surface. A sufficient number of EBP shall be provided for operators and visitors.” (EN 61340-5-1 section 5.3.3)
“EPA ground cords shall be used to make electrical connections between groundable points and the EPA ground facility.” (EN 61340-5-1 section 5.3.4)
Regarding 1 megohm resistor, “A nominal 1 megohm resistor is commonly used in wrist straps and to ground work surfaces.” [EN 61340-5-2: Section 5.1.1] However, for Working Surfaces, it refers to “it is allowed, when approved by the ESD coordinator, to use surfaces which are “hard ground” i.e. less than 1 X 10^4 ohms to EPA ground.” (EN 61340-5-1 Note 6 of Table 1)
“The EPA ground facility shall be connected to EPA ground and provide a low resistance path to EPA ground (<2 ohms). When available, the mains protective earth shall be used. (EN 61340-5-1 section 5.3.2)
When an in-line resistor is used in Charleswater’s common point grounds it is isolated from the banana jacks
Introducing New Conductive Boxes
in these Conductive Boxes
Charleswater Rigid Conductive Boxes are marked with the ESD protective symbol. Boxes can be supplied with or without high density (HD) foam for insertion of component leads or low density (FX) foam which acts as a cushioning material meets EN 61340-5-1 Table 4 Packaging required range for conductive packaging.
- Made of conductive polypropylene;
Rs, Rv: 1 x 10E2 < 1 x 10E5 ohms
per IEC 61340-2-3 - Strong box with integrally hinged lid
- Provide good ESD and mechanical protection
Item | Description | Price |
Box Configuration – No Foam | ||
71240 | Rigid Conductive Box, 35 x 35 x 11mm, Empty | $ 1.00 |
71242 | Rigid Conductive Box, 75 x 51 x 14mm, Empty | $ 2.50 |
71244 | Rigid Conductive Box, 90 x 64 x 16mm, Empty | $ 1.66 |
71246 | Rigid Conductive Box, 108 x 83 x 13mm, Empty | $ 3.00 |
71249 | Rigid Conductive Box, 230 x 128 x 20mm, Empty | $ 5.45 |
71251 | Rigid Conductive Box, 230 x 128 x 30mm, Empty | $ 5.00 |
71253 | Rigid Conductive Box, 230 x 128 x 40mm, Empty | $ 5.50 |
Box Configuration – Foam in Base | ||
71241 | Rigid Conductive Box, 35 x 35 x 11mm, 6mm HD in Base Only | $ 2.16 |
Box Configuration – Foam in Base and Lid | ||
71243 | Rigid Conductive Box, 75 x 51 x 14mm, 6mm HD in Base/FX in Lid | $ 2.78 |
71245 | Rigid Conductive Box, 90 x 64 x 16mm, 6mm HD in Base/FX in Lid | $ 3.49 |
71247 | Rigid Conductive Box, 108 x 83 x 13mm, 6mm HD in Base/FX in Lid | $ 4.03 |
71250 | Rigid Conductive Box, 230 x 128 x 20mm, 6mm HD in Base/FX in Lid | $10.49 |
71252 | Rigid Conductive Box, 230 x 128 x 30mm, 6mm HD in Base/FX in Lid | $12.76 |
71254 | Rigid Conductive Box, 230 x 128 x 40mm, 6mm HD in Base/FX in Lid | $12.91 |
Ground Trolleys in Series With Cords Having 1 Megohm Resistor
Question:
I am confused on ESD connections. I understand that you cannot clip a cord from a wrist strap to the edge of an ESD protective mat. I know that the cord for wrist straps has 1 megohm of resistance and that the point to connect the wrist strap cord should have less than 1 ohm to ground.
I have people using 2 meter high metal rolling trolleys. I believe the preferred method is to connect each trolley directly to a common ground point. Can several trolleys, say 3 to 5 be connected in series with 1 megohm cords with the final cord connected to a ground point or earth bonding point? From what I have read this would only mean about 5 megohms to ground at the furthest cart. I read somewhere something about staying under 35 megohms to ground. Now I cannot find that.
Answer:
The compliance verification limit per EN 61340-5-1 for wrist strap system is less than 3,5 x 10^7 ohms listed in Personnel grounding requirements Table 2. The required limit per ANSI/ESD S20.20 for both working surfaces and mobile equipment (trolleys) is less than 1 x 10^9 ohms resistance to ground listed in EPA requirements Table 3.
It does not do much good to have an operator test their wrist strap using an integrated wrist strap tester as describe in IEC 61340-5-1 Clause A.1, but then work where the matting resistance is added resistance in the path-to-ground.
Although not recommended you could attach the cord for the wrist band to the matting material, and daisy chain the mats and/or trolleys if you could demonstrate that you reliably meet the required limits.
Per CLC/TR 61340-5-2:2008 User guide Wrist Strap subclause 4.7.2.2.2 “NOTE Many wrist strap users have been observed to clip the wrist cord to the edge of an ESD protective mat. This process is not recommended as it can increase the total system resistance to ground to over the 3.5 x 10^7 ohms limit required by IEC 61340-5-1.”
Regarding daisy-chaining “All working surfaces need to be capable of being grounded. EPA grounding of instruments or surfaces by chaining, or by placing items in series should not be used, since in the event of a broken connection the risk of floating items and ESD damage will be unnecessarily increased.” [EN 61340-5-2 clause 5.2.2 Working surfaces and storage racks] Note that both of these recommendations are not requirements.
Regarding ground cords, the grounding conductors (wires) from wrist straps, working surfaces, flooring or floor mats, tools, fixtures, storage units, carts, chairs, garments and other ESD technical elements may or may not contain added resistance. Where added resistance is not present, a direct connection from the ESD technical element to the common ground point or common connection point is acceptable and recommended.
However, “A nominal 1 megohm resistor is commonly used in wrist straps and to ground work surfaces. In the event of an operator touching an energized conductor, for the normal mains electricity supplies this resistor will limit the current flowing through the person to less than 0,5 mA.” [User Guide IEC 61340-5-2-1999 subclause 5.1.1]
Charleswater sells ground cords with and without current limiting resistors – Click Here
Introducing New Dual Operator Continuous Monitor with Satellites
- NEW Improved Banana Jack
Creates a more consistent connection and helps to prevent accidental disconnects with operator’s wrist strap. - Control unit LEDs indicate proper grounding of two mats and two operators; includes mounting hardware
Allows mounting Control Unit at eye level, not using any work surface area - Two Satellite Remote Monitors include monitored wrist strap ground, parking stud, and unmonitored
ground for guest or equipment
Versatile design allowing placement where desired up to 7 feet from control unit. - Audio alarm
- Wave Distortion Technology provides real-time monitoring
Ensures ESD protected workstation, reducing catastrophic failures and latent defects - Utilizes reliable wave distortion technology
Provides true 100% continuous monitoring. - Can use with any brand of single wire wrist strap and coil cord components
Life-cycle costs of monitor / wrist strap / cord are 66% lower than dual-wire approach - Replaces item 99073
- Made in the United States of America
Item | Description | List Price |
99093 | Dual Operator Continuous Monitor with Satellites, 220VAC | $370.68 |