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Q: 110volts vs. 230 volts -- Pros and Cons? ( Answered ,   5 Comments )
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 Subject: 110volts vs. 230 volts -- Pros and Cons? Category: Science > Physics Asked by: burke-ga List Price: \$10.00 Posted: 10 Apr 2002 16:04 PDT Expires: 17 Apr 2002 16:04 PDT Question ID: 182
 ```What are the general pros and cons of using high voltage vs. low voltage for electrical appliances? Some countries like US use 110 volts, some other countries use 230 volts.```
 Subject: Re: 110volts vs. 230 volts -- Pros and Cons? Answered By: drdavid-ga on 10 Apr 2002 16:08 PDT Rated:
 ```Obviously, there is sufficiently little difference in the big picture that both standards have survived in different jurisdictions. (In fact, there are more than two standards: there are places with 110, 120, 130, 220, 230 240 V nominal line voltage [generally +/-6%] plus both 50 and 60 Hz frequency standards. There has been a little progress toward increasing standardization, but it has been very slow.) The existence of the various standards has been largely the result of local politics and historical accident. Roughly speaking, to operate a particular appliance requires a particular amount of POWER, which (at least for resistive loads) is current times voltage. If you double the voltage, you draw half the current to achieve the same power. The primary advantage of lower current is that you lose less power in the wires feeding current to the appliance (or you can use smaller, cheaper wires for the same power loss rating). On the other hand, the higher voltage is somewhat more dangerous if accidentally touched or if there is an accidental short circuit. Some experienced electricians are relatively casual about touching 110 V circuits, but all respect 230 V. (This constitutes a "don't-try-this-at-home thing, though--it's quite possible to get a fatal shock or start a fire with 110 V!) Current trends are toward the use of even lower voltages (24 V, 12 V, 5 V, 3.3 V...) for any devices which don't draw much total power to increase safety. Power is rarely distributed at these lower voltages; rather it is converted from 110 V or 230 V by a transformer at the earliest opportunity. Even in North America, 220-240 V is commonly used in residential appliances for most high-power electrical appliances (ovens, furnaces, dryers, large motors, etc.) so that the supply current and supply wire size can be smaller. Higher power industrial applications often use 480 V or more. And, of course, transmission lines use progressively higher voltages as the distance and total power go up (22,000 V for local distribution to 1,000,000 V for long distance lines). For further reading, one good newsgroup discussion on the issue can be found at sci.engr.lighting: http://groups.google.com/groups?hl=en&threadm=6bg74c%24r7% 40cucumber.demon.co.uk&rnum=12&prev=/groups%3Fq%3Dpros%2Bcons%2B120%2B240% 2Bvolts%26hl%3Den%26start%3D10%26sa%3DN```
 burke-ga rated this answer: `That was very informative. Thanx.`

 Subject: Re: 110volts vs. 230 volts -- Pros and Cons? From: rick-ga on 19 Apr 2002 14:27 PDT
 ```Unless I'm way off, there are some dangerous comments here! Voltage has little to do with the danger of electricty in terms of shock, it's all about current. You could touch 10,000 volts at low current and live, or die with 10 volts at high amperage (current). I don't know about electricians being more cautious with 220, but in america, the difference between 110 and 220 isn't just the voltage, the 220 is also three phase (beyond this question, but it has three active connections instead of two). The amount of available current for these 220 three phase circuits tends to be higher. rick```
 Subject: Re: 110volts vs. 230 volts -- Pros and Cons? From: epeus-ga on 20 Apr 2002 00:27 PDT
 ```The US uses 110V for domestic circuits, but with a centre earth, so the effective potential above ground is 55V. The UK uses 240V, with the neutral line strapped to eath, so the potential above ground is 240V. What hurts is the number of Joules you get. (I x V x time). For a given current, more volts are worse. In addition, higher voltages are more likely to paralyse the nerves, hence keeping you hand stuck on the live wire for longer. Fit a residual-current circuit breaker to detect ground leakage and cut power quickly to reduce the dangers of electrocution. Because 220V will carry about twice the power for the same thickness of wire, electric kettles take about twice as long to boil in the US as in the UK, hence the popularity in the US of stovetop kettles (a utensil I have only seen when camping in the UK).```
 Subject: Re: 110volts vs. 230 volts -- Pros and Cons? From: hedgie-ga on 28 Apr 2002 16:18 PDT
 ```Actually, both comments are way off. Voltage is the driving force of the process we call electric shock. Higher the voltage, other things being the same, means higher current and more absorbed energy (which is measured in Joules). More absorbed energy (in comparable time interval) means higher temperature inside of a cell, which one cause of the damage. Cell starts dying at about 75 C, which is actually used as medical procedure for some conditions, such as BPH. www.jparisi.com/bph/thermotherapy.htm Do not try it at home: If it says "High Voltage" do not speculate about the Joules! Stay away. Voltage is indicator of danger, of the extent of the possible damage. The comment about the kettle is wrong as well. If you import a kettle from Europe and plug it in the US outlet, it will take over 4 time as long to boil the water. It would be a silly thing to do. If you buy one here, made for US voltage, it works as good, as fast, as theirs does there. Since stores here do not carry them, I gor mine at http://www.amazon.com/exec/obidos/tg/stores/detail/-/kitchen/B00004S9H7/104-6935778-87735140 it works fine.```
 Subject: Re: 110volts vs. 230 volts -- Pros and Cons? From: drdavid-ga on 02 May 2002 10:41 PDT
 ```To respond to a couple of the issues raised in the Comments: 1. As Rick notes, it is really current that can injure and kill. You can indeed work safely around kilovolt circuits if the current is limited to safe levels (as it is in many [but by no means all!] products which use such voltages.) However, the current which flows through the body is often limited only by the resistance of the body and the connection to it (the contact resistance at the skin). This is usually the case around typical 110 V and 240 V wiring. In that case, what determines whether or not an injury will occur is the voltage difference between two points of contact (such as a bare wire and ground). The current will be that voltage difference divided by the net resistance (including contact resistance and body resistance). Furthermore, there are often non-linear effects which cause the net resistance to go down with voltage. For example, the current may cause your hand muscles to grasp the live wire harder. That's why higher voltages are more dangerous in accidental contact situations. Certainly, low voltages at high current can also be dangerous. You can even get a nasty injury from, say, a 5 V power supply if you happen to put your hand near an arc from an accidental short circuit of several amps. 2. 220 V circuits in the USA are generated more than one way. In industrial applications, they are usually 3-phase (two versions). Higher-powered residential appliances such as electric ovens, dryers and furnaces use a 2-phase system. The ac power delivered to the house comes in on two wires, both 110 V above ground, but 180 degrees out of phase with each other. Most household circuits provide a connection between one of these lines and a "neutral" or ground wire. The high power devices connect between the two live lines which are 220 V apart. In both cases, there should be (but may not be in some older wiring) a third "ground" wire which should be connected to any metal chassis that may be present in a given appliance. This ensures that the chassis cannot "float" to some voltage that might give you a shock, and that any accidental short circuit to the chassis does not pose a shock hazard. The safety ground wire is physically connected to the neutral wire back at the fuse or circuit breaker box for the house, but only the neutral wire should carry any current under normal conditions. You may also have encountered an additional safety feature which is now required by most electric codes for wet locations (near sinks, outdoors, etc.). This is "GFI" or ground fault interruption. Essentially, there is a local circuit breaker near the point of use which interrupts the circuit if a current leakage to the safety ground lead is detected.```
 Subject: Re: 110volts vs. 230 volts -- Pros and Cons? From: chris2002micrometer-ga on 06 May 2002 10:14 PDT
 ```The higher voltage can deliver twice the energy with the same wire thickness. Insulation is usually the same for both and is rated at 600 volts. I think safety would be greatly enhanced if the circuit was isolated from ground by the utility at the point of entry. If all (US) home appliances used a 230 volt 2-wire (supply and return) from a ground-isolated source, used smaller fuses, and had a third wire to ground any metal surfaces, shock and fire hazards would be substantially reduced. There would be no additional need for isolation transformers and ground-fault interrupt devices. I have a small business (micrometer.com) that deals extensively with electrical utility topics.```