Grounding – Ground Zero Electrostatics Blog

14 Jul

Monitors & Meters: Which One Do You Need?

Monitors and meters may seem like merely a question of semantics. And in most of the world it is, monitors are analogous with meters and vice versa.

But when you’re dealing with electrostatic discharge (ESD) prevention, both have specific purposes and uses that set them apart from one another. And it’s important you know which is which before you start or continue your work with items that can be harmed by ESD.

Monitor: What’s Happening in the Room?

In plain language, in an ESD Prevention situation, the Monitor (noun) keeps known sources of ESD in systematic reviews. It monitors (verb), the ‘progress’ or quality of ESD buildup over a period of time.

So we have monitors for people, that connect to their personal wrist straps, or connect between them and the ESD matting that they are using – in effect, monitoring both.

The key to a good ESD monitor is make sure they provide constant monitoring of the potential ESD in the room. If the monitor fails, a single spark of static electricity can cost hundreds of dollars in damage before it’s quelled.

Meter: Where Is It?

Meters, in an ESD prevention situation, operate more as the means to locate the sources of ESD build up.

Much like the meters used for testing in construction situations, meters will show the relative ESD levels, allowing the user to pinpoint the exact spot where ESD is being generated or not dispersed properly.

This can be on ESD mats, clothing, people and flooring.

Specialty meters can detect and pinpoint ESD specifically in a cleanroom or ionized area.

There are meters that look at a wide variety of potential ESD buildups and smaller units that check select areas only. And meters that check the humidity, temperature, electrical resistance, and any or all of these at once.

There is a secondary subset of meters that you should also be aware of – Testers.

Testers check the grounding of electrical receptacles to ensure they are actually grounded. Imagine the problems and expense of not realizing your electrical plugs were not grounded and subsequently having to discard or repair any sensitive electronics that had been worked on or assembled during the time the ground was inactive.

There are also testers for personal wrist straps and grounding cords.

Are You ESD Aware?

So, the answer to our question above is YES.

It’s not an either/or situation. It’s both. Each tool has its purpose within your ESD control situation, and both are effective in their job – which is generating awareness of ESD.

We would love to be your full service, seamless ESD solution provider; contact us today for more information.

22 Jun

Are You Grounded: A Look at Cables, Clamps, and Drums

Do you remember the cell phone gas fire scares of the early 2000’s? Because of a couple of erroneously spread Internet rumors, people all across the world became convinced that use of their cell phones while at the gas pump could lead to explosions, injuries, even death!

Despite the fact that the rumors were all proven to be false, several gas station chains, including the one whose safety report was misquoted to create the rumors, posted stickers warning against cell phone use. One Chicago suburb even passed a law banning the use of cell phones at gas stations.

If you look closely, those stickers are still on a majority of gas pumps, at least in the US and Canada. But while there has never been a case where cell phones caused gas fires, the same is NOT true for static electricity.

We’ve talked a lot in the past about the danger even a small electroStatic discharge (ESD) can pose to sensitive electronics. But in a combustible atmosphere, that tiny spark can cause a lot more damage than the cost of replacing a damaged circuit board.

Static is Everywhere

Walking across a room, rustling your clothing, even just the act of raising your arm to scratch your nose can generate a sufficient static buildup to create a subsequent ESD if not dissipated. Under normal conditions, you won’t even notice the buildup until you feel the shock of the discharge being released.

When you’re not working with sensitive electronics, you probably don’t even consider this to be a problem, certainly not in your home or driving in your car. But like all charges, if it’s not given a route to ground, the charge continues to build, increasing the voltage. And if you happen to be in an area with flammable liquids, vapors and even dust, that static charge can cause explosive consequences.

The first step to avoid incidents in any environment conducive to these volatile exposures is to eliminate as many potential ignition sources as possible. But there are often unconsidered, hidden dangers, especially in an industrial setting that can act as accidental ignition switches.

Isolated Conductors = Hidden Dangers

Isolated conductors are conductive objects – metal flanges, fittings or valves in pipework systems, portable drums – which are either inherently or accidentally insulated from being grounded. Because of this, any static charge they generate becomes a potential ignition point.

The best way to avoid this problem is by utilizing bonding and grounding. Bonding is the process of joining two or more objects or containers with electrically conductive wires to neutralize the potential charge between them. Grounding is a more specific form of bonding where an object or container is connected to the ground.

There are a variety of ways to effectively employ bonding and grounding. While OSHA does not give clear directives on how to ground, they do specify when and where grounding as well as bonding procedures should exist.

Getting Grounded

The most obvious example to point to is the common ground, seen in every building – a metal rod is attached to the outside of a building and literally grounded a few inches into the soil. While this method works great for homes, the size of large industrial expanses, such as warehouses or factory floors, means other methods may be more suitable.

For manufacturing or large storage areas, there are a few options. They all involve grounding clamps connected to grounding cables.

If the area has access to the building’s main cold water pipe, a very common semi-permanent solution is to use a bronze pipe clamp as an alternative to the direct building ground. C-Grounding clamps are another popular semi-permanent solution. Of course, always check the reliability of the ground conductivity in these instances.

If you’re like many industrial complexes, though, the isolated conductors are often temporary items, like drums, containers and vessels that come and go as needed. For these instances, you can get a variety of steel- or aluminum-constructed clamps that attach to the container, connecting it through a stainless steel cable to a grounding point, making the drum or vessel safe.

Depending on the environment, you can also effectively ground using the drop valve of a mixing tank or connecting your ground cable to a previously grounded surface – a table or workstation that is already connected to the grounding apparatus.

Whatever method you choose, bonding and grounding are essential for the safety of everyone working in an industrial environment, whether they’re piecing together circuit boards, helicopters… or gas pumps.

We would love to be your full service, seamless ESD solution provider; contact us today for more information.

25 May

What Are the Standards for Electrostatic Protection?

So, you’ve just been tasked with building or designing your first Electrostatic Protection Area (EPA). You’ve started doing your research, but there are so many choices, from so many different companies. Suppliers, manufacturers, third party providers… If only there was some established standard for judging the efficacy and reliability of all those pieces and parts.

Well, you’re in luck! In 2007, the American National Standards Institute (ANSI) in cooperation with ElectroStatic Discharge Association (ESDA) released a unified set of standards for the design, implementation and maintenance of ElectroStatic Discharge control programs.

In the midst of World War I, five engineering organizations recognized the need to develop standards that could eliminate confusion and could be adhered to across all disciplines, without regard to politics, profits or personal preferences. These groups reached out to the U.S. Departments of War, Navy, and Commerce to form an impartial third party non-profit organization, then known as the American Engineering Standards Committee.

Following the war, the organization spent the next 20 years establishing several safety protocols still observed today, like eye protection, hard hat standards and in-house electrical safety while at the same time reaching out to other similarly tasked international organizations.

When the United States entered World War II, the organization, which would eventually come to be known as ANSI, helped to accelerate the war effort and productivity, created more effective quality control measures, as well as helping to advance photography, radio, and even the development of Velcro.

In 1970’s, ANSI established a public review process and began the herculean effort of moving the United States to the metric system. While the general public never really connected with the metric system, the effort did bring ANSI to the forefront of private sector companies who discovered standardization was a way to stay more competitive in an increasingly global economy.

With the advancement of personal computers in the late 70’s and early 80’s, engineers at several companies recognized a need for more understanding of electrostatic discharge and its prevention. They formed the ESD Association, a non-profit, voluntary professional organization that for almost 35 years has sponsored educational programs and developed standards to help eliminate losses due to electrostatic discharges.

Together, leaning on the historical experience of both military and several commercial organizations, ANSI and ESDA developed the definitive standard for ESD protection, the very cleverly named ANSI/ESD S20.20-2007.

Covering about every conceivable area of ElectroStatic Discharge, the ANSI/ESD S20.20-2007 utilizes both the human body model and the machine model to provide a broad set of guidelines for ESD protection.

The Human Body Model is the military standard that defines and rates the vulnerability of an electronic device to the ESD generated by a human being touching it. The Machine Model works similarly, except it rates the vulnerability of a device receiving a machine discharge into ground. It was originally developed by car manufacturers as their plants moved to more mechanized production technology. The Human Body Model is about 10 times more sensitive than the Machine Model.

There is a lot to explore in the ANSI/ESD S20.20-2007 guidelines, but for the purpose of this primer, the document highlights 3 fundamental ESD control principles:

All conductors should be grounded. This includes the personnel and the surfaces they are working on. We recommend, at a minimum, personal grounding wrist straps, ESD table or bench mats, and a common ground cord.
Necessary non-conductors – certain circuit board materials, device packaging, etc. – cannot lose their electrostatic charge by being grounded and appropriate precautions must be implemented.
Static protective materials, such as ESD shielding bags or ESD totes and boxes must be utilized when transporting sensitive electronics outside a properly prepared EPA.

There are slightly less stringent standards that apply to floors and bench mats, but ANSI/ESD S20.20-2007 is the highest and most comprehensive guideline so far. So when you’re shopping for the parts needed to establish your EPA area, always look for companies that maintain that standard in their products and services.

We would love to be your full service, seamless ESD solution provider; contact us today for more information.

11 May

10 Common Terms in ESD & What They Mean

In 1865, Lewis Carrol published Alice’s Adventures in Wonderland, at the time, a thinly veiled political commentary wrapped in a fictional form.

Who knew that 150 years later, the book would have spawned several movies, pop cultural references, and a Grace Slick song.

But the most enduring artifact of the novel in today’s world – possibly reinforced by its own self-reference in the Matrix films, is the term “Rabbit hole.” In Alice’s universe, it meant falling into a world of confusion. Today it means losing track of time as you plumb the depths of a topic.

In our effort to be a provider of full service ESD solutions, we give you… The ESD rabbit hole – 10 Common Terms in ESD and What They Mean…

10 Common ESD Terms

The obvious place to start is with the term itself: ESD

ESD stands for ElectroStatic Discharge, a specific type of Electrical Overstress (EOS), defined as the sudden flow of electricity between two electrically charged objects caused by an electrical short, insulation failure, or simple contact. This is most often observed as static electric shock.

Electrical Overstress (EOS) is the exposure of an item to a current or voltage beyond what it can handle. When we’re talking ESD, it’s not just a static shock – because of the nature of sensitive electronics, even just a tiny bit of energy generated by lifting your hand or sliding across a desk can be dangerous enough to damage a component while you’re working, which is shy we recommend common grounding.

Common Grounding is a grounded device where two or more conductors are bonded, or a system for connecting two or more grounding conductors to the same electrical potential. Think of it as a lightning rod for your workstation.

Triboelectric Charging is the generation of electrostatic charges when two materials make contact, or often are rubbed together, then separated. This is what most people call static cling. The polarity and strength of the charges produced differ according to the properties of the materials.

Surface Resistance is measured in Ohms, and tells you how easily an electrical charge can travel across a type of surface. It might be helpful to think in terms of a water pipe analogy. The higher the resistance, the narrower the pipe. In the ESD world, a surface is either conductive or dissipative.

Conductive – A surface is conductive when it has a low resistance, anywhere from no resistance at all, such as water or copper, to mid-level resistance. This would be the wider of the two water pipes.

Static Dissipative – A surface is dissipative when it has a higher resistance, anywhere from the top end of the conductive to so much resistance that only a tiny trickle of “water” comes through the pipe.

Degradation is static electricity damage that weakens an electronic device, while giving the appearance of operating within normal parameters. However, once degraded, a device may fail catastrophically at a later point or just not last as long as it should.

Catastrophic failure is static electricity damage to a device that causes it to cease to function. The device must be replaced.

Ionization is the process by which a neutral atom or molecule acquires either a positive or a negative charge.

To Neutralize is to eliminate an electrostatic field by recombining positive and negative charges, either by conducting the charge to ground or by introducing an equal opposite charge. The charges cancel each other out, leaving a zero charge on the item.

We would love to be your full service, seamless ESD solution provider. For a deeper explanation of any of these terms and how they affect your workplace, contact us today for more information.

05 Dec

Ground Rod-to-earth resistance

Q: What should be the required Ground Rod-to-earth resistance? is it less than 2ohms or less than 25ohms?

A: I am going to consult my document on Grounding-For the Protection of Electrostatics Discharge Susceptible Items (ANSI/ESD S6.1-2005), an ESD Association standard. I am assuming that your inquiry is to provide the bonding and grounding for the prevention of ESD in an EPA (ESD Protected Area).

From the Main(s) service equipment or AC Mains, you have the Hot or Black conductor (Let’s assume AC Single Phase 120v) from the Circuit breaker panel, then you have the Neutral or white conductor coming from the Neutral bus, then you have the Equipment grounding conductor or green conductor. The black or Hot conductor comes from a circuit breaker and goes to an AC outlet receptacle. The white or Neutral conductor comes from a neutral bus which is bonded to an earth grounding electrode and goes to an AC outlet receptacle. The green conductor or equipment grounding conductor comes from a ground bus and is bonded to the metal chassis or conduit. The ground bus is then bonded to the Neutral bus. The common point ground or bus bar is connected or bonded to this ground connection, as is various other ESD technical elements (the grounding conductors or wires from wrist straps, worksurfaces, flooring or floor mats, tools, fixtures, storage units, carts, chairs, garments, etc).

The impedance of the equipment grounding conductor or receptacle ground to the common point ground or ESD technical element shall not be greater than 1 ohm (Ω). I see no mention of 2 ohms (Ω) in this document, although it is noted that the ground resistance values objectives vary from industry to industry. The telecommunications industry has often used 5 ohms or less as their value for grounding and bonding. The goal in grounding resistance values is to achieve the lowest ground resistance value possible. The National Electrical Code defines a ground as: “a conductive connection, whether intentional or accidental between an electrical circuit or equipment and the earth, or to some conducting body that serves in place of the earth.” The purpose of a ground besides the protection of people and equipment is to provide a safe path for the dissipation of Fault Currents, Lightning Strikes, Static Discharges, EMI and RFI signals and Interference.

The reference to 25 ohms refers to facilities with AC Equipment Ground and Auxiliary Ground (A separate supplemental grounding conductor for use other than general equipment grounding) per ANSI/ESD S6.1-2005 6.3.2. The auxiliary ground shall be bonded to the AC equipment ground when possible. The AC equipment and the ESD technical elements might be at different potentials. The auxiliary ground needs to be bonded to the equipment ground to ensure that there is no difference in electrical potential between the two systems.