protective ground An electrical connection or connections to an approved ground for establishing and maintaining a common potential on conductors connected to it. McGraw-Hill Dictionary of Architecture and Construction.
What does protective ground mean?
Protective grounding is what linemen and other utility workers use to protect themselves against the possibility of an electric shock while working on powerlines and circuits.
What are temporary protective grounds used for?
Temporary Protective Ground (TPG) – Cable and clamp assembly designed to limit the voltage exposure at the worksite to a safe value in the event where the line or equipment being worked upon is accidentally energized. They also provide a parallel path for fault current to flow.
What is a personal ground?
1 of or relating to the private aspects of a person's life.
What are the three reasons to place protective grounds before working on an isolated circuit?
Limiting body contact or exposure voltages at the worksite to a safe value if the lines are accidentally energized from any source of hazardous energy. Maximizing personal safety while working on de-energized high-voltage equipment through the use of appropriate protective grounding, procedures and training.
What are the four types of grounds?
Various types of grounds are Broken Ground, Flat and Open Ground, High ground and Dead Ground.
What are the two types of grounds?
There are two kinds of grounding: (1) electrical circuit or system grounding, and (2) electrical equipment grounding. Electrical system grounding is accomplished when one conductor of the circuit is intentionally connected to earth.
What are the types of grounds?
In this article, we'll discuss earth ground, common ground, analog ground, and digital ground. Learn about the basics of grounds, grounding, and ground symbols. Not all grounds are created equal. In this article, we'll discuss earth ground, common ground, analog ground, and digital ground.
What does it mean to bond a ground?
Bonding is the connection of non-current-carrying conductive elements like enclosures and structures. Grounding is the attachment of bonded systems to the earth. Both are necessary to safeguard people and property from electric hazards.
What does being grounded in yourself mean?
Being "grounded" means that you're present in your body and connected with the earth. When you're grounded, you allow yourself to feel centered and balanced no matter what's going on around you. If you aren't grounded, you're like a leaf in the wind: very vulnerable and thrown off balance very quickly.
What is the minimum size for personal protective grounds?
2 AWGThe conductors must be made of multi-stranded copper and can be no smaller than 2 AWG. The primary considerations when selecting grounding cables is their withstand rating for fault current and their length.
When applying protective grounds the first connection should always be?
Always connect to the ground source first and then connect to the conductor or equipment with a live-line tool. OSHA requires the use of a live-line tool to install and remove personal protective grounds. 15.
What is the difference between ground and isolated ground?
1:3610:29What are IG Receptacles and How Do They Work? (Isolated Ground ...YouTubeStart of suggested clipEnd of suggested clipWorks a little bit different it's not connected the same way as a normal ground would be on a normalMoreWorks a little bit different it's not connected the same way as a normal ground would be on a normal receptacle. Sometimes they're also white with like a red triangle.
What is the primary intent of a temporary ground?
Temporary protective grounds shall be placed at such locations and arranged in such a manner that the employer can demonstrate will prevent each employee from being exposed to hazardous differences in electric potential.
What is the purpose of grounds?
Grounding prevents voltage from arcing to other conductive materials such as water and metal, where it could hurt you. Grounding wires also prevent voltage from overloading and damaging your appliances, which will help them last longer and function better.
What is temporary grounding?
Temporary Grounding for Worker Protection is an essential safety reference that shows how to install grounds on de-energized lines, so workers are protected if the lines accidentally become energized.
What is the purpose of an electric ground?
Grounding of electrical equipment has two purposes: To ensure that persons in the area are not exposed to dangerous, electric-shock voltage. To provide current-carrying capability that can accept ground-fault current without creating a fire or explosive hazard.
What is Protective Grounding?
Protective grounding is what linemen and other utility workers use to protect themselves against the possibility of an electric shock while working on powerlines and circuits. Linemen build protective grounds using cables and clamps that effectively ground any electrical current that may pass through the powerlines and circuit being worked on. This is done to protect linemen in case the powerlines are not de-energized or become re-energized due to one of several possible factors.
What do you need to do before you start work?
The final thing you need to do before you begin work is have the grounding tested. The testing is important to ensure the personal protective grounds will protect linemen. Once you have set up the protective grounding, it may be best to hire a professional that can test the protective grounding for you.
What do you need to know before installing protective grounding equipment?
Before installing the protective grounding equipment, you need to make sure it is in perfect working order to effectively protect the linemen. This equipment must be thoroughly inspected prior to installation and cleaned so it will function properly.
Do phase conductors need to be free of oxidation?
The phase conductors and electrodes must be free of oxidation before they are attached to the grounding cables . Make sure you clean these parts using a stiff wire brush to remove any oxidation.
What is a protective ground cable?
Protective ground cables and associated grounding equipment shall meet the following requirements: 1. Capable of conducting the maximum fault current which could occur at the grounded worksite if the de-energized line or equipment becomes energized from any source and for the fault clearing times. A ground or jumper which is sized ...
What devices are allowed in series between the point of connection of the protective grounds and location of contact by the workers?
Connected directly to the equipment, bus, or conductor to be grounded. No impedance or device (circuit breaker, dis connect switch, transformer, line trap, etc.) shall be permitted in series between the point of connection of the protective grounds and location of contact by the workers.
What is a ground jumper?
A ground or jumper which is sized to conduct maximum available fault current should be adequate to safely conduct currents from other sources of hazardous energy, including steady-state currents induced by electromagnetic coupling from nearby energized lines or equipment. 2.
What is double isolation grounding?
The method of double-isolation grounding provides an effective means of isolating equipment for testing.
Can a ground switch be used as a personal protective ground?
Equipment and line terminal ground switches shall not be substituted for personal protective grounds. However, ground switches may be closed in parallel with protective grounds to reduce fault current through the ground cables and lower the worker exposure voltage at the worksite.
Do ground switches carry fault current?
Some types of ground switches are designed for static grounding of equipment and will not carry fault current. Check ground switch ratings before closing in parallel with protective grounds.
Who maintains a list of maximum fault currents at each facility or location where Reclamation employees apply protective grounds?
Regions shall maintain and periodically update a listing of the maximum fault currents at each facility or location where Reclamation employees apply protective grounds.
What is a grounding mat in PPGB?
Grounding mats — Grounding mats are used in PPGB to place workers at the same potential (i.e., voltage) as the equipment on which they are working.
What is a grounding head?
Grounding heads — The grounding head is the only connection between the grounding system and the electrical circuit on which work is to be performed. Like grounding cables, the grounding heads must be rated to withstand the available fault current for the duration of the fault event.
What is the purpose of grounding cables?
Grounding cables — Grounding cables are responsible for providing a low-impedance path for fault current to flow on a properly grounded circuit.
Why do arc flashes happen?
Many arc flash accidents have occurred when workers improperly applied grounding cables and the systems became energized. The techniques for grounding also vary by the types of systems on which work is being performed.
How does a MEPS connect to the Earth?
On metal-enclosed power switchgear (MEPS) the connection to the earth is usually through a grounding bus, which is a metal bar that is, in turn, connected to another grounding electrode. Care must be taken to ensure the grounding bus is effectively connected to the earth via an effective grounding electrode.
What are some examples of sensitive voltage testing devices?
Examples of sensitive voltage testing devices include “proximity” testers, such as glow sticks (similar to light pens), tic-tracers (they make a sound), or direct-reading HV voltmeters. One of the most important steps in the grounding process is to properly clean the conductors before connecting to them.
What is a 3 point test?
A 3-point test consists of testing the voltage tester on a known energized source to verify it is working properly (Test No. 1). Then, test the circuit on which work is to be performed (Test No. 2).
What is the name of the organization that regulates temporary protective grounds?
The Occupational Safety and Health Administration (OSHA) and the American Society for Testing and Materials (ASTM) have established specifications and proper procedures for installing temporary protective grounds.
What is the acronym for temporary protective grounds?
The Occupational Safety and Health Administration (OSHA) and the American Society for Testing and Materials (ASTM) have established specifications and proper procedures for installing temporary protective grounds. The Occupational Safety and Health Administration (OSHA) and the American Society for Testing and Materials (ASTM) ...
What is hot stick?
Hot sticks are often used for proper installation of grounds and jumpers. These auxiliary tools must be in operable working order. ASTM F711-02 has established testing intervals and proper use of fiberglass tools, including hot sticks. Hi-Line Utility Supply cleans, refurbishes and tests over 80,000 fiberglass tools per year.
What are the factors that affect the safety of grounding devices?
Protective grounding devices might look indestructible, but they aren't. Several factors can compromise their safe working capability: • Extreme voltage; • Wear and tear; • Rough treatment; • Accidental pinching; • Moisture; • Nicks, cuts and scratches; and. • Dirt and corrosion on clamps and heads.
What are the two types of ground and jumpers?
Two types of grounds and jumpers are commonly used: personal grounds and running grounds. • Personal grounds are portable devices that temporarily connect a de-energized conductor or pieces of equipment to electrical grounds prior to beginning work.
What is a ferrule cable?
Ferrules: These are the components that attach the stranded grounding cables to the clamp. They are built to industry specifications and include a grade number based on the conductor size they are designed for. Ferrule cable connections include screw compression or crimping to the cable lead.
Why do we need grounding devices?
Grounding devices are designed to help protect line workers and the public from inadvertent electric shock. Safety professionals cite several incidents where line workers can be exposed to a potentially deadly situation: • Human error, which no one can predict; • Higher loads on today's systems; • Lightning;
What is Ground?
In electronics and electrical engineering, it is by convention we define a point in a circuit as a reference point. This reference point is known as ground (or GND) and carries a voltage of 0V. Voltage measurements are relative measurements. That is, a voltage measurement must be compared to another point in the circuit. If it is not, the measurement is meaningless.
What is ESD testing?
The grounding of your test equipment also helps in the elimination of electrostatic discharge (ESD). ESD occurs when a statically-charged body (i.e., you) comes in contact with the test equipment. Some test equipment is ultra sensitive and may be very vulnerable to ESD events.
What is a three terminal DC power supply?
This power supply has a positive (+), a negative (-), and a GND (ground) terminal. As mentioned previously, the ground terminal (earth ground) is physically tied to the chassis, which in turn is connected to the ground wire within the power cord, which is finally connected to the earth via the three prong outlet.
What is noise in grounding?
Such ground currents—think of them as changing currents—when applied to ground return paths, create voltage variations (recall Ohm's Law) called noise. You may have heard the term "a noisy ground." Such noise can compromise sensitive signals in local circuits. Grounding has always been a major obstacle for design, system, and test engineers.
Why is mixed signal grounding important?
Although there are multiple techniques for proper grounding, when it comes to mixed-signal grounding it's of most importance—regardless of which grounding technique is adopted—to separate the "more-noisy" digital return currents from the "less-noisy" analog return currents. This separation of the grounds helps to minimize or prevent noise from being generated within circuits due to ground currents.
What is voltage measurement?
Voltage measurements are relative measurements. That is, a voltage measurement must be compared to another point in the circuit. If it is not, the measurement is meaningless. The ground reference point is often, but not always—more on this later—represented by a standard ground symbol. See Figure 1.
What does the earth ground symbol mean?
The earth ground symbol is, unfortunately, used in many applications in electronics and electrical engineering, often meaning different things to different people, so it may be a bit confusing to some beginners. For instance, the earth ground symbol is also used as a common ground symbol or a 0V reference.
