{"content":{"sharePage":{"page":0,"digests":[{"id":"20493401","dateCreated":"1266827252","smartDate":"Feb 22, 2010","userCreated":{"username":"leeeekian","url":"https:\/\/www.wikispaces.com\/user\/view\/leeeekian","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1266827929\/leeeekian-lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/physicssofun.wikispaces.com\/share\/view\/20493401"},"dateDigested":1532389316,"startDate":null,"sharedType":"discussion","title":"Electric Shock","description":"What damages a person suffers during a severe electric shock? What can you do if you are nearby when a person has an electric shock?","replyPages":[{"page":0,"digests":[{"id":"20861925","body":"Basically there are three factors which affect how severely the person was hurt by a electric shock.
\nFirst, the body's resistence. The main cause of damaging a person is the amount of electricity flow over a person's body. Therefore the higher the body's resistence the less the people the person will demaged.However, this is only apply to the situation whereby the voltage of the current is under 240v, flesh of people will be burnt if the voltage of the current is higher than 240v.
\nSecondly, the path which the current flows through, different part of people have different resistence and this is different according to different people. If the current flow through organs the people will more likely to be killed as their organs are burnt by electricity.
\nLastly, duration of the people being shocked also affect the effect of current on people. The longer the duration, the more the damaging to people.","dateCreated":"1267441567","smartDate":"Mar 1, 2010","userCreated":{"username":"freeisgod","url":"https:\/\/www.wikispaces.com\/user\/view\/freeisgod","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1282122148\/freeisgod-lg.jpg"}},{"id":"20862085","body":"A caution which need to remeber if you need to aid a person being shock by electric current. Do not touch the person if he is holding a wire. People will become a conductor if the voltage is high enough, therefore, the people who touches the person who is shocked will also be shocked.","dateCreated":"1267442570","smartDate":"Mar 1, 2010","userCreated":{"username":"freeisgod","url":"https:\/\/www.wikispaces.com\/user\/view\/freeisgod","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1282122148\/freeisgod-lg.jpg"}},{"id":"20862103","body":"Since I am from St Johns, I shall share with you guys on what we should do if we noticed somone getting an electric shock.
\n
\nFirstly, we have to step on an insulated object such as a mat and use another insulated object to off the electrical mains.
\nNext, we will notice that there will be a entry and exit point of the electricity on the casualty's body.
\nThen, douse the entry and exit wounds with water for 10minutes to cool the burns and ease the pain.
\nFinally, cover the wounds with a single layer of bandage so as to prevent infection. A single layer of bandage is used so as to allow heat loss.
\nAlso, turn him to recovery position to open the casualty's airway for him to breathe easily.
\n
\nThanks
\n
\nShengYang","dateCreated":"1267442748","smartDate":"Mar 1, 2010","userCreated":{"username":"4a118shengyang","url":"https:\/\/www.wikispaces.com\/user\/view\/4a118shengyang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20863157","body":"Also be careful with the STEP voltage if there is a wire which transfer very high voltage lies on the ground because a human could get severe electric shock when he is standing with two feet separated. This is due to the high difference in potential difference caused by the high voltage spreading through the ground.
\nElectric current could travel through on leg to another and causes people to fall down. Once one falls down in this high voltage circle, he will experience severe electric shock which current travels through important organs, causing death. Thus, if there is a high voltage wire lying on the ground, we should jump with only on foot touching the ground each time and gradually get out of the voltage circle.","dateCreated":"1267447365","smartDate":"Mar 1, 2010","userCreated":{"username":"Boliang4A105","url":"https:\/\/www.wikispaces.com\/user\/view\/Boliang4A105","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20865189","body":"When a person has an electric shock, the injuries range from a mild tingling sensation like static to instant death (electrocution). Nerves around the body like the brain and spinal cord are extremely sensitive to electricity. Electric shocks may cause simple nerve damage that is self-regenerative or severe and permanent brain and nerve damage. Electric shocks cause death mostly because of damage to the cardiovascular and respiratory systems. Electric shocks paralyze the respiratory system and disrupt the beating of the heart, causing instant death by electrocution. Smaller veins and arteries also clot easily, stemming blood flow to the body parts. This causes the body parts to \u201cdie\u201d and amputation is required after the electric shock. Electric shocks can also cause failure of major organs like kidney and destroy muscles in the body. Muscle spasms that occur during the electric shock can also cause tissue damage or bone damage. Burns, both mild and severe, will scar the skin. Infection of these wounds commonly causes death in electric shock patients.
\nSeverity of an electric shock depends on 6 different factors, namely
\n1) the voltage of the electric current
\n2) the amount of current (amperage)
\n3) the type of current (direct current or alternating current)
\n4) the skin\/body\u2019s resistance to the current
\n5) the path of the current into the body
\n6) length of contact with the electric current
\n
\nThin or Wet skin is less resistant to electricity than thick or dry skin. When skin resistance is low, external injuries like burns will be milder but the electricity will burn and damage internal organs and tissues. When skin resistance is high, external burns will be more severe but internal injuries will be milder.
\n
\nWhen an electric shock occurs, immediately switch off the main electric power. If this cannot be done, stand on a non-conducting object like newspapers or cardboards to push the victim away from the electric source. Alternatively, use a wooden broom or stick to push the person away immediately. Never touch the victim while the electric current is still flowing. Emergency ambulance should be called simultaneously. After the electric shock ceases, persons trained in CPR or resuscitation should perform first aid while emergency help arrives.","dateCreated":"1267450874","smartDate":"Mar 1, 2010","userCreated":{"username":"zhonghao4A103","url":"https:\/\/www.wikispaces.com\/user\/view\/zhonghao4A103","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20871711","body":"elecric shock may blow a person away suddenly, and also it can make a person's muscles to contract. Longtime under elecric shock or high voltage electric shock may cause permanent disability or even death.
\n
\ntreatment\uff1a
\n1.turn off the main switch
\n2.move the person away from the electrical resource using a dry and non-conductive object.
\n3.call the ambulance","dateCreated":"1267457425","smartDate":"Mar 1, 2010","userCreated":{"username":"HaoShizhong4a107","url":"https:\/\/www.wikispaces.com\/user\/view\/HaoShizhong4a107","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20908961","body":"To save a person who has got electric shock, the first thing is to disconnect him from the electric source, turn off the electric source, and use an wooden bar to remove the wire from the person.","dateCreated":"1267491821","smartDate":"Mar 1, 2010","userCreated":{"username":"ZouKL","url":"https:\/\/www.wikispaces.com\/user\/view\/ZouKL","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20910827","body":"The person may experience tingling or numbing sensations, become uncounscious or cause tissue and nerve damage. We should disconnect the power supply then call the ambulance.","dateCreated":"1267493418","smartDate":"Mar 1, 2010","userCreated":{"username":"WaiKiu","url":"https:\/\/www.wikispaces.com\/user\/view\/WaiKiu","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20911733","body":"The higher the current, the longer the time of the shock current, the more severe the injuries. The severity of injuries depends on which part of the body does the shock current flow through. The most serious effect is when the current flow through the heart. If a live wire accidentally touches the body by contact at the head, the nervous system will be severely damaged. If during the accident the victim\u2019s right hand touches the live wire, while the left hand is holding the metal casing of the washing machine, the electrical current will flow through the chest. Then the lungs and heart will probably be injured. A higher skin resistance will lower the shock current. The current is inversely proportional to the resistance. If the victim\u2019s body is dry, then the shock current through his body will be lower. Then the injury will be less severe.","dateCreated":"1267494173","smartDate":"Mar 1, 2010","userCreated":{"username":"4a1isaac","url":"https:\/\/www.wikispaces.com\/user\/view\/4a1isaac","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20916817","body":"During a severe electric shock, tbe high current will cause tissue damage, burns, ventricular fibrillation in which there is uncoordinated contraction of the cardiac muscle of the ventricles in the heart, making them quiver rather than contract properly, leading to cardiac dysrhythmia (abnormal electric activity in the heart), and finally cause blood circulation to cease, or sudden cardiac death. Other neurological adverse effects would include neuropathy, which is the damage to some of the nerves in the nervous system.
\n
\nIf a person experiences electric shock, first turn off the main electric source in that area, if unable to do so, use a material which is a poor conductor of electricity, e.g a wooden pole, to push\/move the victim away from the current. If there are burns inflicted onto the victim, remove jewellery and any tight clothing and cover these burns with a clean sheet of cloth. Try as much as possible not to move the victim as he may have suffered fractures, in that case, await the ambulance's arrival","dateCreated":"1267499387","smartDate":"Mar 1, 2010","userCreated":{"username":"Joseph_Lim","url":"https:\/\/www.wikispaces.com\/user\/view\/Joseph_Lim","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20923609","body":"An electric shock occurs upon contact of a human body with any source of voltage high enough to cause sufficient current through the muscles or hair. The minimum current a human can feel is thought to be about 1 milliampere (mA). The current may cause tissue damage or fibrillation if it is sufficiently high. Death caused by an electric shock is referred to as electrocution. Generally, currents approaching 100 mA are lethal if they pass through sensitive portions of the body.
\n
\nDamage caused by electrical shocks can be classified into the following categories:
\n
\nBurns
\n
\nHeating due to resistance can cause extensive and deep burns. Voltage levels of 500 to 1000 volts tend to cause internal burns due to the large energy (which is proportional to the duration multiplied by the square of the current multiplied by resistance) available from the source. Damage due to current is through tissue heating.
\n
\nVentricular fibrillation
\nA low-voltage (110 or 230 V), 50 or 60-Hz AC current through the chest for a fraction of a second may induce ventricular fibrillation at currents as low as 60 mA. With DC, 300 to 500 mA is required. If the current has a direct pathway to the heart (e.g., via a cardiac catheter or other kind of electrode), a much lower current of less than 1 mA (AC or DC) can cause fibrillation. If not immediately treated by defibrillation, fibrillations are usually lethal because all the heart muscle cells move independently. Above 200 mA, muscle contractions are so strong that the heart muscles cannot move at all.
\n
\nNeurological effects
\nCurrent can cause interference with nervous control, especially over the heart and lungs. Repeated or severe electric shock which does not lead to death has been shown to cause neuropathy.
\n
\nWhen the current path is through the head, it appears that, with sufficient current, loss of consciousness almost always occurs swiftly. (This is borne out by some limited self-experimentation by early designers of the electric chair and by research from the field of animal husbandry, where electric stunning has been extensively studied.)","dateCreated":"1267515731","smartDate":"Mar 1, 2010","userCreated":{"username":"4a113_KuikWJ","url":"https:\/\/www.wikispaces.com\/user\/view\/4a113_KuikWJ","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20991541","body":"the person suffers from burns as tissues in his body are heated. furthermore, since processes in the body are control by electrical impulses, the electric shock may interfere with the signals, causing the heart and breathing to stop even. to help the person, first we break the contact between the person and the electrical source. then we call for emergency assistance. if the person is unconscious and not breathing, perform CPR.","dateCreated":"1267606497","smartDate":"Mar 3, 2010","userCreated":{"username":"4a109bangying","url":"https:\/\/www.wikispaces.com\/user\/view\/4a109bangying","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":27}]},{"id":"20493383","dateCreated":"1266827131","smartDate":"Feb 22, 2010","userCreated":{"username":"leeeekian","url":"https:\/\/www.wikispaces.com\/user\/view\/leeeekian","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1266827929\/leeeekian-lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/physicssofun.wikispaces.com\/share\/view\/20493383"},"dateDigested":1532389317,"startDate":null,"sharedType":"discussion","title":"Ring Main Circuit","description":"In what ways is a ring-main circuit like a parallel circuit? In what ways it is different from a parallel circuit?","replyPages":[{"page":0,"digests":[{"id":"20857707","body":"A ring final circuit (also ring main circuit) is an electrical wiring technique developed and primarily used in the United Kingdom that provides two independent conductors for live, neutral and earth wires within a building for each connected load or socket.
\nA parallel circuit has more than one resistor and gets its name from having multiple paths to move along . Charges can move through any of several paths. If one of the items in the circuit is broken then no charge will move through that path, but other paths will continue to have charges flow through them. Parallel circuits are found in most household electrical wiring.","dateCreated":"1267424059","smartDate":"Feb 28, 2010","userCreated":{"username":"nicholas23","url":"https:\/\/www.wikispaces.com\/user\/view\/nicholas23","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20860109","body":"The ring circuit or ring main as it is often called starts at the consumer unit and returns to the consumer unit. It can serve an area up to 120 square yards. It is normally protected by a 30 amp fuse or 32amp circuit breaker, it can have any number of sockets or fused connection units on it but the maximum load is 7200 watts.
\n
\nA Parallel circuit is one where the current flows in several circuits (or 'branches') at the same time. The reason for parallel electrical circuits is to limit the amount of current in each cable.","dateCreated":"1267433255","smartDate":"Mar 1, 2010","userCreated":{"username":"chowwenkang","url":"https:\/\/www.wikispaces.com\/user\/view\/chowwenkang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20923145","body":"The ring circuit or ring main as it is often called starts at the consumer unit and returns to the consumer unit. It can serve an area up to 120 square yards. It is normally protected by a 30 amp fuse or 32amp circuit breaker, it can have any number of sockets or fused connection units on it but the maximum load is 7200 watts
\n
\nIn a single-phase system, the ring starts at the consumer unit (also known as fuse box or breaker box), visits each socket in turn, and then returns to the consumer unit.
\n
\nA parallel circuit is a circuit that has more than one resistor (anything that uses electricity to do work) and gets its name from having multiple (parallel) paths to move along . Charges can move through any of several paths. If one of the items in the circuit is broken then no charge will move through that path, but other paths will continue to have charges flow through them.
\n
\nThe similarity between these two electrical system is that even when one of the items in either of the circuits is broken, electrical charges will still flow through them. Thus both circuits are found in most household electrical wiring. This is done so that lights don't stop working just because you turned your TV off.
\n
\nKuik Wei Jian
\n4A113","dateCreated":"1267514214","smartDate":"Mar 1, 2010","userCreated":{"username":"4a113_KuikWJ","url":"https:\/\/www.wikispaces.com\/user\/view\/4a113_KuikWJ","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":0}]},{"id":"20493375","dateCreated":"1266827088","smartDate":"Feb 22, 2010","userCreated":{"username":"leeeekian","url":"https:\/\/www.wikispaces.com\/user\/view\/leeeekian","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1266827929\/leeeekian-lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/physicssofun.wikispaces.com\/share\/view\/20493375"},"dateDigested":1532389318,"startDate":null,"sharedType":"discussion","title":"Power of a Heater","description":"Which heating element (used in water heaters) converts more electrical energy to thermal energy per second, one with 25 ohm resistance or another with 38 ohm resistance, when connected to the same voltage supply of 240 V? Explain.","replyPages":[{"page":0,"digests":[{"id":"20859967","body":"For appliances that convert electrical energy to thermal energy, P = V^2\/R
\n
\nAs the voltage is constant (240 volts), the resistance must be low to obtain a high value of P. Hence, the one with the 25 ohm resistance can convert more electrical energy into thermal energy.","dateCreated":"1267432471","smartDate":"Mar 1, 2010","userCreated":{"username":"chowwenkang","url":"https:\/\/www.wikispaces.com\/user\/view\/chowwenkang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20860791","body":"It is the 38ohm resistance. During the process of elctrical energy converting to the heat energy, the bigger the resistance is, the larger amount of heat energy is converted.","dateCreated":"1267435977","smartDate":"Mar 1, 2010","userCreated":{"username":"HaoShizhong4a107","url":"https:\/\/www.wikispaces.com\/user\/view\/HaoShizhong4a107","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20861093","body":"From the formula, P=(V^2)\/R
\nV is constant at 240V because of the constant power supply.
\n
\nSubsituting the numbers, When R = 25,
\n
\nP = 240^2 \/ 25
\n
\nWhen R = 38,
\n
\nP = 240^2\/ 38
\n
\nAs 240^2\/25 > 240^2\/38,
\n
\nThus, the one with the 25 ohm resistance can convert more electrical energy to thermal energy per second
\n
\nToh Jia Hui 4A130","dateCreated":"1267436825","smartDate":"Mar 1, 2010","userCreated":{"username":"jiahui94","url":"https:\/\/www.wikispaces.com\/user\/view\/jiahui94","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20861227","body":"The one with 38 ohm resistance can convert more electrical energy to thermal energy. According to Joule's First Law, the heat produced is proportional to the square of the current multiplied by the electrical resistance of the wire. Therefore when the current is constant, a higher amount of resistance will allow more electrical energy to be converted to hear energy.","dateCreated":"1267437507","smartDate":"Mar 1, 2010","userCreated":{"username":"4a134bingru","url":"https:\/\/www.wikispaces.com\/user\/view\/4a134bingru","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20861379","body":"The electric heater with 25 ohm can convert more electric energy to thermal energy.
\nWe can obtain this result by useing formula
\nP=IV
\ntherefore, p=V^2\/R
\nwhen the resistence is bigger the power being converted became less. Therefore, the one with 25ohm of resistence will convert more electric energy to thermal energy","dateCreated":"1267438402","smartDate":"Mar 1, 2010","userCreated":{"username":"freeisgod","url":"https:\/\/www.wikispaces.com\/user\/view\/freeisgod","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1282122148\/freeisgod-lg.jpg"}},{"id":"20861477","body":"First, we need to find out the voltage of both heating elements.
\n
\n
\nAs the voltage supply is the same, the current will be the same. Due to the equation V=IR, as resistance increases, the voltage required also increases. Hence, the heating element with a resistance of 38ohm has a voltage than the heating element with a resistance of 25ohm
\n
\nBy using the equation P=V^2\/R,
\n
\nHeating element with 38ohm resistance,
\n
\nP=1444I^2\/38=38I
\n
\nHeating element with 25ohm resistance,
\n
\nP=625I^2\/25=25I
\n
\nHence, the element with 38ohm resistance converts more electrical energy to heat energy per second.","dateCreated":"1267438959","smartDate":"Mar 1, 2010","userCreated":{"username":"4A111_IvanEng","url":"https:\/\/www.wikispaces.com\/user\/view\/4A111_IvanEng","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20871187","body":"P= V2\/R
\nWhen R increases, P decreases as V is 240 V. The amount of electrical energy converted to heat energy per unit time decreases. Therefore, the heating element (used in water heaters) with the 25 ohm resistance converts more electrical energy to thermal energy per second.","dateCreated":"1267456938","smartDate":"Mar 1, 2010","userCreated":{"username":"4A115derborne","url":"https:\/\/www.wikispaces.com\/user\/view\/4A115derborne","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20910467","body":"The 38ohm resistance heater. As V=IR As current is constant, V increases as R increases as it comes from the same voltage supply of 240 V. Thus the amount of electrical energy converted to thermal energy will increase when the resistance increases.","dateCreated":"1267493081","smartDate":"Mar 1, 2010","userCreated":{"username":"WaiKiu","url":"https:\/\/www.wikispaces.com\/user\/view\/WaiKiu","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20911085","body":"Correction: the 25ohm resistor. V=IR as the voltage is constant, current increases ad resistance decreases. Thus the amount of electrical energy converted to thermal energy will increase as resistance decreases.","dateCreated":"1267493639","smartDate":"Mar 1, 2010","userCreated":{"username":"WaiKiu","url":"https:\/\/www.wikispaces.com\/user\/view\/WaiKiu","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20914457","body":"When there is resistance, electricity is lost in the form of heat energy. Hence, the more resistance is present, more electricity is converted into heat energy. Hence, the 38 ohm resistor will convert more energy into heat energy","dateCreated":"1267496563","smartDate":"Mar 1, 2010","userCreated":{"username":"4a129taypangshiang","url":"https:\/\/www.wikispaces.com\/user\/view\/4a129taypangshiang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20917605","body":"The more electrical energy there is, the more thermal energy is produced.
\n
\nP=V^2\/R
\n
\nAs the resistance increases, the power will decrease, and the amount of electrical energy will be decreased. Therefore, 25ohm resistor, having a lower resistance, will allow more electrical energy to flow through, and be converted into thermal energy.","dateCreated":"1267500546","smartDate":"Mar 1, 2010","userCreated":{"username":"Joseph_Lim","url":"https:\/\/www.wikispaces.com\/user\/view\/Joseph_Lim","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20991587","body":"Using the formula P=(V^2)\/R , where V is the 240V that is supplied, it can be seen that P is inversely proportional to R. When R increases, P decreases. Hence, the heater with the 25 ohm resistance can convert more electrical energy into thermal energy as R is small, giving a bigger value of P.","dateCreated":"1267606689","smartDate":"Mar 3, 2010","userCreated":{"username":"4a109bangying","url":"https:\/\/www.wikispaces.com\/user\/view\/4a109bangying","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":11}]},{"id":"20493371","dateCreated":"1266827045","smartDate":"Feb 22, 2010","userCreated":{"username":"leeeekian","url":"https:\/\/www.wikispaces.com\/user\/view\/leeeekian","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1266827929\/leeeekian-lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/physicssofun.wikispaces.com\/share\/view\/20493371"},"dateDigested":1532389319,"startDate":null,"sharedType":"discussion","title":"Rating for Wires","description":"Wires used for electric circuits in the homes are rated. Why is rating necessary? Why lighting flex can only be used for lighting circuit?","replyPages":[{"page":0,"digests":[{"id":"20856913","body":"The main function of a voltage rating is to ensure that the user of the wiring or the device that contains the wiring can reasonably expect to utilize the material and not encounter danger to self or the device. From this perspective, the voltage rating will specify how much electrical current can safely be carried through the wiring, as well as defining the type of current that can be safely conducted through the wire. Observing the standard set by the voltage rating greatly diminishes the opportunity for overheating and electrical fires.
\nDepending on the construction and intended use of the wiring, the voltage rating may clear the wire for a high amount of voltage. As an example cable voltage ratings for MI cable is usually within the range of one thousand volts. Wiring for table lamps and other household appliances would be much lower.","dateCreated":"1267421660","smartDate":"Feb 28, 2010","userCreated":{"username":"4A133CJ","url":"https:\/\/www.wikispaces.com\/user\/view\/4A133CJ","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20857137","body":"The main function of a voltage rating is to ensure that the user of the wiring or the device that contains the wiring can reasonably expect to utilize the material and not encounter danger to self or the device. From this perspective, the voltage rating will specify how much electrical current can safely be carried through the wiring, as well as defining the type of current that can be safely conducted through the wire. Observing the standard set by the voltage rating greatly diminishes the opportunity for overheating and electrical fires.
\n
\nThere is no wired device in use today that has not been tested and certified with a voltage rating. Depending on the construction and intended use of the wiring, the voltage rating may clear the wire for a high amount of voltage. As an example cable voltage ratings for MI cable is usually within the range of one thousand volts. Wiring for table lamps and other household appliances would be much lower.
\nBy setting a voltage rating that specifies the highest amount of current that the wiring can carry and still operate within acceptable safety limits, the voltage rating makes it possible for governments and other jurisdictions to set standards for wiring used in all sorts of applications. Wiring for use in setting up the electrical system for a residential home must meet specific manufacturing standards and be awarded a voltage rating within a given range. The same is true for wiring in public buildings. Many types of machinery used in the production of goods and services must also contain wiring that meets standards and a voltage rating that is considered reasonable for the amount of current the machine will need in order to function long term.","dateCreated":"1267422321","smartDate":"Feb 28, 2010","userCreated":{"username":"junda94","url":"https:\/\/www.wikispaces.com\/user\/view\/junda94","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20857591","body":"excuse me, is not that my answer ... jun da please read before you post.
\n
\nVoltage ratings are evaluations based on research and experimentation that help to determine how much voltage can be safely utilized by a particular form of wiring. The voltage rating will take into consideration the materials used to construct the wiring, the thickness of the actual cable design of the wiring, and the intended use of the wire. A scale of voltage rating is established for all forms of electrical wiring in use today.","dateCreated":"1267423769","smartDate":"Feb 28, 2010","userCreated":{"username":"4A133CJ","url":"https:\/\/www.wikispaces.com\/user\/view\/4A133CJ","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20858085","body":"The purpose of voltage reading is to give the user of electric appliances an idea of the amount of and type of electric current that could be flowing through the wiring, hence letting the user have a better understanding and estimation of how to use the appliance appropriately without incurring any dangers to self and others. Hence rating is necessary to ensure the safety of users.
\n
\nToh Jia Hui 4A130","dateCreated":"1267424828","smartDate":"Feb 28, 2010","userCreated":{"username":"jiahui94","url":"https:\/\/www.wikispaces.com\/user\/view\/jiahui94","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20860063","body":"The purpose of rating is to let the user know how much current is passing through the wire so that the required voltage can operate gadgets at home.","dateCreated":"1267432984","smartDate":"Mar 1, 2010","userCreated":{"username":"chowwenkang","url":"https:\/\/www.wikispaces.com\/user\/view\/chowwenkang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20911939","body":"Voltage rating is for the allocation of a reasonable amount of energy to a certain appliance so that just the required amount flows through the appliance. This serves two purposes, one is to prevent the wastage of surplus electricity, second to reduce the risk and severity of an electric shock as there is less electricity flowing in the appliance","dateCreated":"1267494342","smartDate":"Mar 1, 2010","userCreated":{"username":"4a129taypangshiang","url":"https:\/\/www.wikispaces.com\/user\/view\/4a129taypangshiang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20923487","body":"Voltage ratings are evaluations based on research and experimentation that help to determine how much voltage can be safely utilized by a particular form of wiring. The voltage rating will take into consideration the materials used to construct the wiring, the thickness of the actual cable design of the wiring, and the intended use of the wire. A scale of voltage rating is established for all forms of electrical wiring in use today.
\n
\nVoltage rating usually refers to the insulation of the wire but could be terminology for electrical equipment also. In North America standard voltage ratings of wire are 300, 600, 1000, 5Kv, 15 Kv and 25 Kv.
\n
\nVoltage Ratings are important as it give the maximum voltage a component can withstand without breaking down. Thus, with such values, user can better utilize the mechanism better without safety risk or risk of mechanism breaking down.
\n
\nKuik Wei Jian
\n4A113","dateCreated":"1267515352","smartDate":"Mar 1, 2010","userCreated":{"username":"4a113_KuikWJ","url":"https:\/\/www.wikispaces.com\/user\/view\/4a113_KuikWJ","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20924119","body":"Voltage ratings are evaluations based on research and experimentation that help to determine how much voltage can be safely utilized by a particular form of wiring. The voltage rating will take into consideration the materials used to construct the wire, the intended use of the wire and the thickness of the cable. In North America, standard voltage ratings of wire are 300, 600, 1000, 5Kv, 15 Kv and 25 Kv.","dateCreated":"1267518285","smartDate":"Mar 2, 2010","userCreated":{"username":"4a1isaac","url":"https:\/\/www.wikispaces.com\/user\/view\/4a1isaac","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":0}]},{"id":"20493363","dateCreated":"1266827003","smartDate":"Feb 22, 2010","userCreated":{"username":"leeeekian","url":"https:\/\/www.wikispaces.com\/user\/view\/leeeekian","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1266827929\/leeeekian-lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/physicssofun.wikispaces.com\/share\/view\/20493363"},"dateDigested":1532389320,"startDate":null,"sharedType":"discussion","title":"Why 240 volt?","description":"Electricity mains supply is alternating current (AC). Many different standards apply. The electricity supply in UK and other Commonwealth countries is a 240 volt AC, where the actual voltage varies from about minus 340 volts to plus 340 volts in a continuous wave 50 times per second. The US supply is similarly alternating, but goes from plus 155 volts to minus 155 volts at a frequency of 60 cycles per second.
\n
\nDiscuss the advantages and disadvantages of each 240 V and 110 V electricity supply in terms of usage & safety.","replyPages":[{"page":0,"digests":[{"id":"20858653","body":"The advantages of the 240V power supply are that it is easier to operate devices that require high voltage, and that lesser current is needed for loading. It is also more efficient as with less flow of current, there would be less energy lost as heat because the resistance in the wire is constant, and so as the voltage increases the current drops and the current is what causes heat production in resistors.
\n
\nHowever, it is not as safe compared to the 110V as higher voltage may cause more severe injuries if mishandled. Also, in the 240v supply, as a higher insulation level for wire and equipment are needed compared to the 110v supply, more cost would be needed.
\n
\nThe advantages of the 110V are that electricity can be transferred over long distances at an optimum level with little loss in power, and that it is safe as the severity of the potential electrical hazards from it is lesser than the 240V. The disadvantages are it is harder to operate devices that require high voltage, and that more current is needed for loading.
\n
\nToh Jia Hui 4A130","dateCreated":"1267426523","smartDate":"Feb 28, 2010","userCreated":{"username":"jiahui94","url":"https:\/\/www.wikispaces.com\/user\/view\/jiahui94","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20859459","body":"P = IV. If we use the 240 Volts, we can use less current to reach the same amount of watts needed to operate some appliances. We do this so as to lower the amount of energy lost as heat energy when electrical energy passes through the wires which have a certain level of resistance, as there would be lower current flowing through the wires.
\n
\nFor the 110V, less power is lost and thus can withstand further distances, which is very important in big countries like USA so as to minimize losses","dateCreated":"1267430229","smartDate":"Feb 28, 2010","userCreated":{"username":"TWK_4a128","url":"https:\/\/www.wikispaces.com\/user\/view\/TWK_4a128","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20859913","body":"The advantage of 240 volts would be that higher voltages can transfer more power, over thinner cables, with less heat generated. Thinner cables are cheaper, and easier to run. However, higher voltages are more dangerous for people, and require more insulation to keep the electricity contained.
\n
\nThe advantage of 110 volts is that there is one less wire and one less breaker for each circuit, hence it is relatively safer as compared to 240 volts.","dateCreated":"1267432240","smartDate":"Mar 1, 2010","userCreated":{"username":"chowwenkang","url":"https:\/\/www.wikispaces.com\/user\/view\/chowwenkang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20861763","body":"P=IV
\n
\nBy using 240V, less current is needed to operate electrical appliances that need a large amount of electrical energy. Hence, thin wires can be used and this reduces cost.
\n
\nHowever, a 240V is much more dangerous and insulation of wires are needed to contain electricity.
\n
\nP=V^2\/R
\n
\nHence when using 110V, less power is lost. It is also safer due to the lower voltage.","dateCreated":"1267440542","smartDate":"Mar 1, 2010","userCreated":{"username":"4A111_IvanEng","url":"https:\/\/www.wikispaces.com\/user\/view\/4A111_IvanEng","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20870267","body":"The advantages of the 240 V power supply:
\n- makes it easier to operate devices that require high voltagel
\n- a lesser current is needed
\n- more energy efficient
\n
\nThe disadvantages of the 240 V power supply:
\n- higher voltage may cause more severe injuries during accidents
\n- less energy efficient
\n
\nThe advantages of the 110 V power supply:
\n- little loss in power
\n- safer than the 240 V power supply
\n
\nThe disadvantages of the 110 V power supply:
\n- harder to operate devices that require high voltage
\n- more current is needed for loading","dateCreated":"1267456050","smartDate":"Mar 1, 2010","userCreated":{"username":"4A115derborne","url":"https:\/\/www.wikispaces.com\/user\/view\/4A115derborne","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20871151","body":"The 240V electricity supply has a higher voltage, hence will provide more power as compared to the 110V one. Also, it requires thinner cables to be transmitted, and it also is able to be transmitted for a long distance without much loss in power. Hence, it is more economic viable. However, due to it's greater power, it may also cause instant death due to electrocution upon contact, hence, it needs to be properly insulated, else may become a health hazard.
\n
\nThe 110V electricity supply on the other hand, though supplying less voltage and hence power, is relatively safer as compared to the 240V electricity supply. It might give you a mild shock, but will not cause death. On the other hand, the 110V voltage requires cables of bigger diameter, hence increasing the costs. Also, the supply will find trouble in powering appliances with a higher voltage requirement. Therefore, it also has its disadvantages","dateCreated":"1267456921","smartDate":"Mar 1, 2010","userCreated":{"username":"Joseph_Lim","url":"https:\/\/www.wikispaces.com\/user\/view\/Joseph_Lim","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20871193","body":"240V enable anything to work easier or with less effoet so it will be cheaper.
\n240V is more dangerous than 110V, when you grab a conductor, 240V will blow you away while 110V will cause your muscles to involuntarily contract.
\n240V can served the large appliances like ovens and dryers but 110v is close to the original Edison ones.","dateCreated":"1267456951","smartDate":"Mar 1, 2010","userCreated":{"username":"HaoShizhong4a107","url":"https:\/\/www.wikispaces.com\/user\/view\/HaoShizhong4a107","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20906449","body":"The advantage of 240V is that it requires less power to operate devices while 110V (used in USA) uses more power to operate as the energy given to electrons. The advantage of the 110V is that it can be transferred at an optimum level for long distances with short loss in power in wire while for 240V it have greater loss in power Moreover, 240V draws less current to achieve the same power. In terms of safety, the lower voltage is safer if there is an accidental short circuit or when you are exposed to live wire. If you touch a 110V wire, you will not be affected much. However if you used the 240V, it might be fatal.
\n
\n
\nTan Xin Ren 4A1","dateCreated":"1267489362","smartDate":"Mar 1, 2010","userCreated":{"username":"4A127xinren","url":"https:\/\/www.wikispaces.com\/user\/view\/4A127xinren","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20908525","body":"compare to with 110V, 240V has less loss of electricity during the transfer. If we assume the loss of the electricity of 240V and 110V are the same, the cross-sectional area of wire of 240V is just a half of the cross-sectional area of wire of 110V. 240V also reduces the workload of the electricity transformer.
\nSo in a word, the advantage of 240V is it saves energy and material of wire, reduces the workload of the device.","dateCreated":"1267491373","smartDate":"Mar 1, 2010","userCreated":{"username":"ZouKL","url":"https:\/\/www.wikispaces.com\/user\/view\/ZouKL","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20911593","body":"P = IV
\nwhen 240v is used compared to a lower voltage, less current is needed to generate the same power. Hence, less electricity is lost during the transfer. However, as the voltage is higher, it is more dangerous when a person comes into contact with a live wire carrying 240v of electricity","dateCreated":"1267494056","smartDate":"Mar 1, 2010","userCreated":{"username":"4a129taypangshiang","url":"https:\/\/www.wikispaces.com\/user\/view\/4a129taypangshiang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20918683","body":"Higher voltage means that the loss of power during the process of transmission is reduced as there is smaller current.But it is more dangerous comparing with low voltages.","dateCreated":"1267502186","smartDate":"Mar 1, 2010","userCreated":{"username":"4A108HengYuqiang","url":"https:\/\/www.wikispaces.com\/user\/view\/4A108HengYuqiang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"20991435","body":"240v needs less power to deliver the same amount of energy than the 110v and needs less current to achieve the same amount of power. However, the 240v is more dangerous than the 110v as the voltage is higher and can cause more serious injuries during accidental contact","dateCreated":"1267606104","smartDate":"Mar 3, 2010","userCreated":{"username":"4a109bangying","url":"https:\/\/www.wikispaces.com\/user\/view\/4a109bangying","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":3}]}],"more":false},"comments":[]},"http":{"code":200,"status":"OK"},"redirectUrl":null,"javascript":null,"notices":{"warning":[],"error":[],"info":[],"success":[]}}