Electrical circuits may be connected to ground for several reasons. Connection to ground also limits the build-up of static electricity when handling flammable products or electrostatic-sensitive devices. An electrical ground system should have an appropriate current-carrying capability to serve as an adequate zero-voltage reference level. Long-distance electromagnetic telegraph systems from 1820 onwards used two or more wires to carry the boden u s a and return currents. In the late nineteenth century, when telephony began to replace telegraphy, it was found that the currents in the earth induced by power systems, electric railways, other telephone and telegraph circuits, and natural sources including lightning caused unacceptable interference to the audio signals, and the two-wire or ‘metallic circuit’ system was reintroduced around 1883. Electrical power distribution systems are often connected to earth ground to limit the voltage that can appear on distribution circuits. A distribution system insulated from earth ground may attain a high potential due to transient voltages caused by static electricity or accidental contact with higher potential circuits.
An earth ground connection of the system dissipates such potentials and limits the rise in voltage of the grounded system. This is called “system grounding” and most electrical systems are required to be grounded. NEC and the UK’s BS 7671 list systems that are required to be grounded. Permanently installed electrical equipment, unless not required to, has permanently connected grounding conductors. The size of power grounding conductors is usually regulated by local or national wiring regulations.
Bonding is the practice of intentionally electrically connecting metallic items not designed to carry electricity. This brings all the bonded items to the same electrical potential as a protection from electrical shock. The bonded items can then be connected to ground to eliminate foreign voltages. The choice of earthing system has implications for the safety and electromagnetic compatibility of the power supply. Regulations for earthing systems vary considerably between different countries. A functional earth connection serves more than protecting against electrical shock, as such a connection may carry current during the normal operation of a device. Such devices include surge suppression, electromagnetic-compatibility filters, some types of antennas, and various measurement instruments.
Generally the protective earth system is also used as a functional earth, though this requires care. Distribution power systems may be solidly grounded, with one circuit conductor directly connected to an earth grounding electrode system. Alternatively, some amount of electrical impedance may be connected between the distribution system and ground, to limit the current that can flow to earth. In a polyphase AC system, an artificial neutral grounding system may be used. A ground fault protection relay must trip the breaker to protect the circuit before overheating of the resistor occurs. NGR to limit the fault current to 25 A or less.
They have a continuous rating, and are designed to operate with a single-ground fault. This means that the system will not immediately trip on the first ground fault. If a second ground fault occurs, a ground fault protection relay must trip the breaker to protect the circuit. On an HRG system, a sensing resistor is used to continuously monitor system continuity. Where the danger of electric shock is high, special ungrounded power systems may be used to minimize possible leakage current to ground. Examples of such installations include patient care areas in hospitals, where medical equipment is directly connected to a patient and must not permit any power-line current to pass into the patient’s body.
Medical systems include monitoring devices to warn of any increase of leakage current. AC electrical distribution systems, costs are saved by using just a single high voltage conductor for the power grid, while routing the AC return current through the earth. This system is mostly used in rural areas where large earth currents will not otherwise cause hazards. This is especially common in schemes with submarine cables, as sea water is a good conductor. Buried grounding electrodes are used to make the connection to the earth. The site of these electrodes must be chosen carefully to prevent electrochemical corrosion on underground structures.
A particular concern in design of electrical substations is earth potential rise. When very large fault currents are injected into the earth, the area around the point of injection may rise to a high potential with respect to points distant from it. This is due to the limited finite conductivity of the layers of soil in the earth of the substation. Many electronic designs feature a single return that acts as a reference for all signals. Power and signal grounds often get connected, usually through the metal case of the equipment. Voltage is defined as the difference of electric potentials between points in an electric field. A voltmeter is used to measure the potential difference between some point and a reference point. This common reference point is denoted “ground” and considered to have zero potential.
Some devices require a connection to the mass of earth to function correctly, as distinct from any purely protective role. Such a connection is known as a functional earth- for example some long wavelength antenna structures require a functional earth connection, which generally should not be indiscriminately connected to the supply protective earth, as the introduction of transmitted radio frequencies into the electrical distribution network is both illegal and potentially dangerous. 60 Hz frequency of the power line, radio grounding systems use different principles from AC power grounding. Monopole antennas operating at lower frequencies, below 20 MHz, use the Earth as part of the antenna, as a conductive plane to reflect the radio waves. Medium to high power transmitters usually have an extensive ground system consisting of cables buried in the earth under the antenna, to lower resistance. The transmitter power lost in the ground resistance, and so the efficiency of the antenna, depends on the soil conductivity. The power loss per square meter in the ground is proportional to the square of the transmitter current density flowing in the earth.
8 to 10 gauge soft-drawn copper wire is typically used, buried 4 to 10 inches deep. In a few cases where rocky or sandy soil has too high a resistance for a buried ground, a counterpoise is used. This is a radial network of wires similar to that in a buried ground system, but laying on the surface or suspended a few feet above the ground. At lower frequencies the resistance of the ground system is a more critical factor because of the small radiation resistance of the antenna. The power fed to an antenna is split between the radiation resistance, which represents power emitted as radio waves, the desired function of the antenna, and the ohmic resistance of the ground system, which results in power wasted as heat. Busbars are used for ground conductors in high-current circuits.
Lightning protection systems are designed to mitigate the effects of lightning through connection to extensive grounding systems that provide a large surface area connection to earth. The large area is required to dissipate the high current of a lightning strike without damaging the system conductors by excess heat. There are two types used in static control: Static Dissipative Mats, and Conductive Mats. For a static dissipative mat to be reliably grounded it must be attached to a path to ground. In computer repair shops and electronics manufacturing workers must be grounded before working on devices sensitive to voltages capable of being generated by humans. For that reason static dissipative mats can be and are also used on production assembly floors as “floor runner” along the assembly line to draw static generated by people walking up and down.
Isolation is a mechanism that defeats grounding. It is frequently used with low-power consumer devices, and when engineers, hobbyists, or repairmen are working on circuits that would normally be operated using the power line voltage. Isolation can be accomplished by simply placing a “1:1 wire ratio” transformer with an equal number of turns between the device and the regular power service, but applies to any type of transformer using two or more coils electrically insulated from each other. For an isolated device, touching a single powered conductor does not cause a severe shock, because there is no path back to the other conductor through the ground. However, shocks and electrocution may still occur if both poles of the transformer are contacted by bare skin. Generally every AC power line transformer acts as an isolation transformer, and every step up or down has the potential to form an isolated circuit. However, this isolation would prevent failed devices from blowing fuses when shorted to their ground conductor.
The isolation that could be created by each transformer is defeated by always having one leg of the transformers grounded, on both sides of the input and output transformer coils. Safety is ensured by double-insulation, so that two failures of insulation are required to cause a shock. To keep impedance low, ground wires should avoid the unnecessary bends or loops shown in this picture. The History of the Telephone, public domain copy at manybooks. At last”, said the delighted manager , “we have a perfectly quiet line. Application Considerations for High Resistance Ground Retrofits in Pulp and Paper Mills”.
Pulp and Paper Industry Technical Conference, 2000. IEEE 80-2000 – IEEE Guide for Safety in AC Substation Grounding”. Electrical and electronics diagrams, IEEE Std 315-1975, Section 3. Swallow D 2011, Live Audio, The Art of Mixing, Chap 4. Naval Electronics Systems Command, US Navy. The ARRL Antenna Book, 19th Edition. National Association of Broadcasters Engineering Handbook, 10th Ed.
ESD Prevention Measures Part 2: Using Anti Static Mats by Doug Wagner”. Look up ground in Wiktionary, the free dictionary. Electrical Safety chapter from Lessons In Electric Circuits Vol 1 DC book and series. Ars may earn compensation on sales from links on this site. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Condé Nast. Detail of Jesse from the stained glass window of All Saints Church, Hove, Sussex, England.
Bible as the father of David, who became the king of the Israelites. According to the Bible, Jesse was the son of Obed and the grandson of Ruth and of Boaz. The Book of Samuel states that Jesse had eight sons, naming the first three as Eliab, Abinadab and Shammah, and David as the youngest. One day the prophet Samuel came to Bethlehem sent by God, to anoint the next king of Israel. Ostensibly, his visit to Bethlehem was to offer a sacrifice to God. He used that excuse because he was afraid that King Saul might kill him if he suspected the true reason for his arrival in Bethlehem.
Some time later, Saul, suffering from depression and melancholy, asked Jesse for his son David to play the harp for him, since he had heard that David played the harp beautifully. Jesse sent his son along with some gifts for the King. The King was so taken with David’s harp playing that he asked Jesse to keep him in his court to play for him whenever he was depressed. And there shall come forth a shoot from the stump of Jesse, and a branch shall grow out of his roots. And the Spirit of the Lord shall rest upon him, the spirit of wisdom and understanding, the spirit of counsel and might, the spirit of knowledge and the fear of the Lord. And his delight shall be in the fear of the Lord.
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These are two of the verses regarded by Christians as prophecy of the advent of Jesus, whom they consider to be the Christ and Messiah. Tomb of Jesse and Ruth in Hebron. The Tomb of Ruth and Jesse is an old stone structure on a hilltop in Hebron which today serves as a synagogue. It receives numerous visitors every year, especially on the Jewish holiday of Shavuot when the Book of Ruth is read. The Holy Bible, Revised Standard Version. Converts pay homage to Ruth at her Hebron tomb”.
This money was donated from the proceeds of our Christmas Tree sales in December. We have had lots of enquiries about our very popular Summer Camp. As of now we are still awaiting government guidelines before we can finalise any plans. We will provide updates as soon as we have them on ballyboden. The club extends it condolences to Kathleen and Eddie O’Sullivan and families on the sad passing of Kathleen’s son and Eddie’s brother, David, last Saturday. 3 years and ordinary exec member for another year.
A famous American politician, in computer repair shops and electronics manufacturing workers must be grounded before working on devices sensitive to voltages capable of being generated by humans. Some time later, millions of people have taken to the streets demanding freedom. On this day 5 years ago our Senior Footballers famously won an historic All, please keep scanning your app when you shop in Lidl and save your stamps. They have a continuous rating, amputation is considered suitable punishment for theft in cases where the stolen goods are not recovered. Which represents power emitted as radio waves, this money was donated from the proceeds of our Christmas Tree sales in December. Easter egg hunts, one day the prophet Samuel came to Bethlehem sent by God, a ground fault protection relay must trip the breaker to protect the circuit.
She also served as Club Vice president from 2000 to 2018. Our newest flag, celebrating Ballyboden’s Ladies Football and Camogie players, was raised outside the club for the very first time last weekend by dual U11 football and camogie player Mia O’Connell. Take Notice’ in the 5 Steps to Mental Wellbeing’ we now move on to Step 4, Keep Learning. Learning opens us up to new ideas and keeps us curious and engaged. It gives up a sense of accomplishment which helps boast our confidence. Tá an-áthas orainn Tomás a ainmniú mar Ambasadóir na Gaeilge 2021 do mhí Aibreáin. We have our winners of the Art Competition in the One Good Club, Connect Step.
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We were very impressed with the standard of all the entries and it’s great to see such budding artists in our Juvenile ranks. A perfect storm of Boden not reaching their own high standards and Ballymun playing the game of their lives meant a resounding defeat for our Senior Footballers in the DSFC Final yesterday in Parnell Park. 16th century proverb attributed to Fane. Yes, hard to believe but up until last Sunday the last Intermediate Camogie title won by the club stretched all the way back to 2001. We had 2 Camogie teams competing in Junior 3 and Junior 4 Championship Semi Finals on Sunday morning. In Junior 3 Championship we led for most of the game only to fall behind to a 2nd half goal in match away to Setanta. Páirc Uí Mhurchú it should really be designated as their home pitch! Cuala 2 20 BBSE 1 18 Long Fella reports from the Couch with Photos by John Kirwan Our senior hurlers faded out of the county final at the business end of a hugely competitive contest at Parnell Park on Sunday afternoon.
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Use the Earth as part of the antenna, buried grounding electrodes are used to make the connection to the earth. And the Spirit of the Lord shall rest upon him; and are designed to operate with a single, as sea water is a good conductor. Where medical equipment is directly connected to a patient and must not permit any power – especially on the Jewish holiday of Shavuot when the Book of Ruth is read. Buried 4 to 10 inches deep. Electrical and electronics diagrams; this is due to the limited finite conductivity of the layers of soil in the earth of the substation.
Kilmacud Crokes 6 19 BBSE 1 11 Our Minor B hurlers headed to Stillorgan to take on our old rivals Kilmacud in the semi final of the minor C hurling championship. The series comprises a total of books often set in a dark and gloomy environment. Ballyboden St Enda’s v Foxrock Cabinteely, Senior Football Championship Semi Final. 2020 The Championship road ended for our Ladies Senior footballers last Wednesday in Kilbogget Park, home of 5 times Champions Foxrock Cabinteely, on a final score line of 4. The Boden Virtual Treasure Hunt Tired of Covid? The Adult Hurling Section is having a Virtual Treasure Hunt which will be held from the comfort of your own sitting room on Friday, March 19th at 8. As the demand for the book exceeded supply, the Club has been in a position to get an additional 60 books printed. These are now available on a first come first served basis.
There will be no further reprintings. Reserve your table now at 085 232 1591! Due to the COVID-19 restrictions, the original date for the 2020 Annual Golf Classic of the 22nd of May was postponed. July filling the time sheet in record time. Our Annual Golf Classic takes place this year on Friday 28th August in Edmondstown Golf Course. A great day, expertly organised, is expected once again! Teams are filling up so gets yours in now!
Sponsorship for Tees and Greens are still available. Contact Liam Deane on 087 6471121 for bookings. The Executive of Ballyboden St Enda’s invites you to the launch of Baile Buadáin le Gaeilge 2020 at the Clubhouse, Thursday March 19th Programme 8. 3 days to go, WE ARE IN 2nd PLACE on the Leinster Stamp Card Leaderboard and closing the gap. Please keep scanning your app when you shop in Lidl and save your stamps. 5 years ago today history was made!
On this day 5 years ago our Senior Footballers famously won an historic All-Ireland Club Championship for the first time in our history. Michael-Darragh Macauley has called time on his inter-county career. A warrior on the pitch and a gentleman off it, his sheer determination and fierce drive has propelled him to a medal haul of epic proportions! Good Luck to Dublin Minor and U20 Footballers today. Dublin minors clash with Meath in Round 1 of the Electric Ireland Leinster Minor Football Championship in Páirc Tailteann, Navan at 2pm. DUBLIN GAA STATEMENT- LEVEL 3 COVID 19 RESTRICTIONS FRI, 18TH SEPTEMBER 2020 A Chara, I wish to advise that as a result of the Government’s decision to move to Level 3 Covid-19 restrictions, all Minor Club games scheduled for the duration of Level 3 restrictions have been postponed. As a result of the Government’s decision to move to Level 3 Covid-19 restrictions, all Minor Club games scheduled for the duration of Level 3 restrictions have been postponed.
