| MisledAaron |
I have read most of the threads and noticed that allot of people have said about the risk of fire.
I am doing a computer and electronic technology course and one of the things we have learn is of we make something which uses mains power is to "get it checked", I personal don't want to hear that someone started there projector up and got realy hurt or coursed a fire losing there house.
If you make or repair an item that is connected to the mains supply and it is NOT CHECKED your house and contants insurance may not be covered (this even means adding extra power plug), just some advise take your DIY projector to someone to see if is OK and get them to cert it, so if there is a fire you have covered yourself. :) .
BE SAFE!!!!! I'm not trying to put anyone off because i love this site and love DIY. If you are new to DIY and want to learn good on ya ;) and there are lots of great peope here to help you learn. |
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| bulldog5046 |
just out of interest surly if your using a computer psu there is no need to get it checked because it already has been and anything after it is only 12V, i'm sure there must be more to this infomation because imagen u bought a floodlight and you had to wire it up, you wouldn't have to go get it checked would you? if u caqn see what i mean? the person who wired it up could use non reinforced cabeling and then cut though it or somthing later, would that void his insurence? i'm not trying to criticise you just saying that there must be variables to this information.
Thanks,
Ryan Edge |
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| bboyquick |
| I have a fire extinguisher on the top floor and kitchen and basement.. thats a goood precaution for any house! |
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| faithblinded |
We're not making our own power supplies. We're simply taking off the shelf UL listed electronics and turning them into something else. I think most of us sit by our projector when we use it. And turn it off when not. Pretty simple. If it starts to smolder, we'll smell it cause we'll be in the room. Why do you think there are a million threads about heat control?
'Get it chcked' by whom? WE can't exactly afford to have Underwriters Laboratories test our designs. This is DIY, at your own risk. Besides, the time it takes to set up and test a projector should be enough to find out if it's a toaster oven not a projector.
Besides, the risk of fire here doesn't really have anything to do with electricity. It's the bulbs. They get too damn hot. But heat control has to be a focus for any high wattage projector. You should be worried if we WEREN'T talking about heat control. Fortunately though, it is clear to almost all that these bulbs are mini suns, and consequently pump crazy heat.
As far as mains voltage go. yes it is dangerous, particularly outside the USA where people have 220+ standard. 110 will bite ya, but 220 will grab ya. The difference is large. Be careful people. Never work on a live circuit. Double check you are unplugged before tearing things apart, etc.
It's DIY, at your own risk. I know if my house burns down on account of some DIY project gone haywire, it's the last thing I'd tell my insurance company after the fact. Not very likely, but hey I'm not gonna hand the shady, bloated, doesn't give a damn about me, insurance company a reason not to pay for it. My lips would be sealed, as should anyone else's. Don't volunteer info to the insurance company they can screw you with.
All that said, it is a good point to remind people of. Be careful, we're not playing with LEGO's here. You can get shocked, burned, hurt with power tools. Keep your wits about you and follow your safety rules. Make sure your bulb has good airflow. Buy a digital thermometer with a probe and alarm if necessary, so the alarm goes off when the probe detects a certain temp. Or just integrate a thermal switch. These would have been good things to suggest besides "get it checked" lol. I still don't know who would check it. Please elaborate. |
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| MisledAaron |
in the question of who to take it to, well there is a number of people electrician for one if something did go worry they have it on record that it was checked.
As for fire risk it isn't just the heat that can course a fire there is a possiblitly of connections arcing if not connected right, someone may not know about earthing if using a metal case (notice few people using computer cases), using heat shrink over connections. these are things that they would check!,
here we have 240v :hot: .
As for not telling the company if you don't inform them that it was DIY and the fire investigator says it was this item that coursed it the company would void it, the investigators are pretty good at finding the course and knowing what the was before it was charcoaled.:apathic:
I'm not trying to be a stick in the mud :bawling: I just passing information on that i learnt.
in cases miss wiring coursing pain and even death or loss can put you in the court!!
I'm going to take my one in to cover my *** and to make sure my family is safe, plus some of these are behind and who is going to watch it and the movie at the sametime. |
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| BlackDog |
MisledAaron is stating what is true for his locality. The electrical code in New Zealand is very strict, and you literally are not allowed to change a plug without violating one of the codes. Obviously people DO change plugs, but it's just another excuse for insurance companies to not pay out if they have any inkling that they equipment that caused the fire was non-standard.
When I came over from England, all this shocked me as the Electrical Code is much more liberal there.
I do find these laws very frustrating, as it's very expensive to get an eletrician in just to change a light switch etc...
SteveM |
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| MisledAaron |
| Thanks blackdog you also cleared something up for me, i didn't know that the laws aboard were so different, to find out the laws in your areas look up at your countrys gov web site the rules and regulation codes would be posted on there site or connect local health and safety, for rules and regulations. |
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| faithblinded |
Electricians aren't electrical engineers. Sure, they can tell you if your light is wired properly, and they can look at some heat shrink and say "nice". But they're not generally as famaliar with electronics type circuits and what safety measures should be taken with them. And I certainly don't believe any insurance company is going to be satisfied because an electrician said it looked OK to him/her, documented or not. If they think the projector was the fault of the fire, and they find a way not to cover it, they will. That's the claims person's job. Find a way out of paying for it. I don't think you'll ever be able to truly satisfy an insurance company until your PJ is UL listed or tested by some other similar testing standards. UL certification is big bucks.
I guess I just think you're being an alarmist. And talking about the insurance company seems like an alarmist scare tactic lol. Safety is important, but this isn't a commercial enterprise. And most of the people undertaking this project understand there are dangers involved. It's part of the nature of DIY. I just think if you're gonna go off on a "be careful of fire rant", you should offer some better suggestions than "get it checked". It's not likely many people will do that. And I'm pretty convinced it'll do no good in the insurance company's eyes, if something goes wrong. It might give you the pice of mind of knowing you hooked things up all correctly. In which case, if that's what you're looking for, by all means, make SURE things are hooked up correctly by referring to someone that knows. Most likely that means coming here to the DIY community. But don't go to an electrician expecting to have some magic protection from the insurance company if you burn your house down. Not gonna happen.
So here's a few safety guidelines of my own for the newbs out there:
1. BE CAREFUL!!! lol Keep your wits about you, and if you've had a few too many beers or other recreational drugs lol, please stay out of the shop and away from the tools!
2. NEVER work with live electricity. Always ALWAYS check to make sure something you're going to work on is NOT plugged in. This is especially important to people in countries with high voltage power(200V +). As Aaron suggested, bare copper is a BIG NO NO!! Arcing inside your projector will not be a good thing to hear. Or feel if it jumped to your metal enclosure and then to you. Which is why it's important to ground those metal enclosures. You don't want to be the shortest path to ground. So cover that copper up. Heat shrink, electrical tape. Please don't use duct tape on wiring lol. Heat shrink is preffered, and looks nice to boot, when you can use it. Whole books have been written on electrical safety. Fortunately, the most complicated thing most will run into is wiring their light. But if you're using relays to control all your items or anything else more complicated, obviously more things come into play. One more thing, important to us. Be careful with power supplies people. The caps in a PC power supply can hold juice for a long time, and some of them are high voltage. A 30V cap discharging into you doesn't feel good. DC current will really give you a good whack, so be careful. If you can use your power supply without taking it apart, do, and you won't have to worry about it.
3.Don't mount a bulb next to a piece of wood without ventilation. Good ventilation. Don't underestimate how much heat your bulb produces. Too much airflow is better than not enough. Don't be skimpy with your fans, and make airflow an integral part of your design. If the noise bothers you spend the extra few bucks on the low decibal fans.
4.Power tools are not toys. Be careful. When using a table saw, always let the blade stop before you remove your material. Same goes for mitre saws and most any rotary blade tool. Make sure the guard closes on a circular saw before you set it down, EVERY TIME YOU USE IT!! You'd be amazed at the velocity a small chunk of wood or acryilic can pick up from a circular blade. Easily enough to put out an eye. So wear your safety glasses! Try and use your dominant hand for tools whenever possible. Every extra bit of control with power tools is important. A cheap pair of leather gloves is a great way to keep your hands safe from the nicks and cuts of the workshop, and save you from the deeper cuts sometimes. Please note leather doesn't protect you from electricity! Turn it off!
heh that's enough for now. I have to feed the kids.
Codes across the globe vary widely, as do insurance policies. If you're really worried, find the fine print in your fire insurance policy and read it with a fine toothed comb. Not a bad idea to look into local codes either, if you like. |
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| ace3000_1 |
| quote: | Originally posted by bulldog5046
just out of interest surly if your using a computer psu there is no need to get it checked because it already has been and anything after it is only 12V, i'm sure there must be more to this infomation because imagen u bought a floodlight and you had to wire it up, you wouldn't have to go get it checked would you? if u caqn see what i mean? the person who wired it up could use non reinforced cabeling and then cut though it or somthing later, would that void his insurence? i'm not trying to criticise you just saying that there must be variables to this information.
Thanks,
Ryan Edge |
Yess very true but a computer power supply is designed to be run in a computer and only designed for a computer, Aron is right in this case.
Abit of info for ya, running a comp psu only on the 12v can cause a fire or burn out your panel, how so you might think, well on a computer power supply they are designed to have the 5v line run with the 12v line, the 3.3v with the 5v ect, just running the 12v and not using the 5v will cause the voltage of the 12v line to rise, the more you draw on the 12v line the higher that voltage will rise, in some cases upto 30volts drawing 5amps. You must use the 5v line at a certain amperage to keep the 12v line at 12v!, or you may soon see your beloved panel burning out its regulators from over voltage rersulting in fire or damage to your panel. Also have you ever seen a 12v line on a compter run at 12v in a computer?
Aron is also right about insurance, weather its a simple halogen flood light or a wall socket, anything thats not carried out by a qualified personel will not enable you to get the insurance. This also goes for moddifications to certified equiptment. You will find that if your house did burn down from an electrical fault and after it was investigated, (and beleive me they are good these investigators), and they ask you who did the wiring, and say you lie, you will soon find yourself in court or jail for fraud and for carrying out activities you are not licensed nor trianed to carry out. If you say it was done by you and if you dont have the license to prove you are allowed to conduct such activities then you wont get insurance, possibly also murder charges if there was a case of death. That goes for any country and why we have qualified personel, its all about saftey.
Trev:) |
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| ace3000_1 |
| quote: | | Electricians aren't electrical engineers. Sure, they can tell you if your light is wired properly, and they can look at some heat shrink and say "nice". But they're not generally as famaliar with electronics type circuits and what safety measures should be taken with them. |
Actually they are an engineer, electritions are licensed engineers to deal with ac wiring, not low voltage dc. An electrical technition is an engineer that is qualified to work on or repair such items as tv's, vcr's ect, they do abit of both, but by no means house wiring like an electrition is ltrained to carry out. Now and electrical engineer is a person who designs circuts, they design prety much anything, but there are also different types of specific electrical engineers aswell, its a ladder of difference and all are licensed to carry out their work specificly.
I know one thing for sure faith, say somthing did happen to my house and if there was a death or fire, i know that i wouldnt like to carry that weight on my shoulders unlicensed, or at all in any case. Sure we all are diy guru's and hell ive done some repairs that im not licensed to carry out, but i always make sure that i tripple check everything before the power is aplied, and use common sence in the way of thinking what could happen down the track on any particular item that may be at a risk or could be a risk in any way. Ive also got a good sound knewlege on electronics that ive been doing since i was 9, im now 27, manny in here dont even know what a resistor is, diy can be a risky bussiness in anything, and somtimes we all need to be reminded of the flipside of the trade.
A question for ya, is it realy worth your life to fix the tv yourself to save a few bux?
As for insurance companies i think we all know they are crooks.
As for 110v vs 240v, they both kill, 110v can actually be more of a killer then 240v as the 110v carries a higher amperage, i was shocked the otherday by a cap that didnt discharge, it was 400v, why didnt i die? cos the amperage was too low, but i can tell ya, i felt it. being electricuted doesnt mean you will die either there are a few things to consider, like state of health, how long you wer shocked for ect, but one thing is for sure, never under estimate what electricity could do to you.
Trev:) |
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| faithblinded |
I wasn't trying to downplay the value of electricians, and wasn't really trying to argue their being called engineers or not. My best friend is a commercial Sparky, and he's the man. I was just saying a sparky isn't necessarily an electronics expert. Certainly that doesn't mean they won't have any good ideas or advice for someone less skilled with electricity. Their advice can be invaluable.
Nor was I trying to downplay the value of safety. I just didn't want anyone to get scared out of the DIY water by the fear of fire. Scared into being more careful is perfectly acceptable lol.
I was talking about mains when I was talking about 110 vs 220, in which case I'd almost always rather be hit by the 110. Obviously I'd rather avoid both. I hate electricity induced giggling. heh. That's what 110 does to me. Of course, not every instance is the same. The resistance of a person's body can vary greatly, and therefore the amount of juice required to kill fluctuates as well. It'd probably be hard to let go of a 110 line if you just got out of the shower, because the water would have made your body far less resistant.(bummer) I know you prolly know this stuff Ace, just tryin to throw useful info in the post for all the newbs readin this stuff. Hopefully we can make them extra careful.
Contrary to what many people might think, it only takes amperage in the milliamps to do permanent damage or kill a person. Granted, in most situations it will take alot of voltage to give someone that much juice, because the body is such a major resistor, but there are definitely times it will take less. And from what I read, it takes even less juice to harm the ladies or smaller folks. Electricity is no joke.
I'm gonna find my safety book and list some of the different physiological effects of different amperages. It's really interesting stuff..... |
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| bobharry |
| quote: | | possibly also murder charges if there was a case of death |
Wouldn't it be manslaughter, oh well I won't go OT. As for safely using pc psu's couldn't you put resistors on the unused lines so there is still power being used from them? Also what you say is very true, the amperage on 110v has to be a lot higher than on 200v+ (almost 2 times) to run the equipment, and what a lot of people don't realise is that it is the amps that kills you. So if there was a few thousand volts at 50ma (don't ask me how you'd get it that low, just an example) it wouldn't kill you, you might not even feel it with that lower amperage (haven't tried so I couldn't be sure). |
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| mathias |
| quote: | | Now and electrical engineer is a person who designs circuts, they design prety much anything. |
Thank you, hm.... wonder what I haven´t designed yet.:)
Most electrical engineers are not licensed to install or work with high level voltages devices, we have the knowledge but we don´t handle any high level voltages, but thats what an electrician do.
When we talking electric safety do always use a platic cover and you will be pretty safe. All connections must also be in a plastic cover, the important is that you can´t touch any conductive parts. When you test a circuit with 110V or 240V and you must measure some voltage or current, first connect your meterwires and make sure you can´t touch any conductive parts, place the whole thing in a plastic box (not the meter) start the meter and last connect the thing to the main voltage, when you have got your result from the meter, disconnect the thing from the main voltage the first thing you do and always check two times if you have disconnected it.
There is one thing I must warn you all about PSU, ballast and all primary switched devices have big capacitors and they are loaded with over 400V even if you disconnect the device from the main voltages. Do absolutely NOT touch these. |
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| faithblinded |
| quote: | Originally posted by bobharry
Also what you say is very true, the amperage on 110v has to be a lot higher than on 200v+ (almost 2 times) to run the equipment, and what a lot of people don't realise is that it is the amps that kills you. So if there was a few thousand volts at 50ma (don't ask me how you'd get it that low, just an example) it wouldn't kill you, you might not even feel it with that lower amperage (haven't tried so I couldn't be sure). |
Amperage is a measure of load. It is relevant to current and resistance according to Ohm's law. I assure you, you would feel a few thousand volts, even if the delivery system was capable of handling only 50 mA. Amperage figures are used to define how much of a load a system can handle, not how much is there. It's only relevant to the load provided by the resistor(person) in the path of the electricity. Please don't ever touch a line that's 1000 volts plus just because you think it's only carrying 50mA. That would be a seriously regrettable mistake.
| quote: | Originally from the book, Lessons in Electronic Circuits, Vol 1, by Tony R. Kuphaldt, 5th Edition no changes have been made
Most of us have experienced some form of electric "shock," where electricity causes our body to experience pain or trauma. If we are fortunate, the extent of that experience is limited to tingles or jolts of pain from static electricity buildup discharging through our bodies. When we are working around electric circuits capable of delivering high power to loads, electric shock becomes a much more serious issue, and pain is the least significant result of shock.
As electric current is conducted through a material, any opposition to that flow of electrons (resistance) results in a dissipation of energy, usually in the form of heat. This is the most basic and easy-to-understand effect of electricity on living tissue: current makes it heat up. If the amount of heat generated is sufficient, the tissue may be burnt. The effect is physiologically the same as damage caused by an open flame or other high-temperature source of heat, except that electricity has the ability to burn tissue well beneath the skin of a victim, even burning internal organs. Another effect of electric current on the body, perhaps the most significant in terms of hazard, regards the nervous system. By "nervous system" I mean the network of special cells in the body called "nerve cells" or "neurons" which process and conduct the multitude of signals responsible for regulation of many body functions. The brain, spinal cord, and sensory/motor organs in the body function together to allow it to sense, move, respond, think, and remember.
Nerve cells communicate to each other by acting as "transducers:" creating electrical signals (very small voltages and currents) in response to the input of certain chemical compounds called neurotransmitters, and releasing neurotransmitters when stimulated by electrical signals. If electric
current of suffcient magnitude is conducted through a living creature (human or otherwise), its effect will be to override the tiny electrical impulses normally generated by the neurons, overloading the nervous system and preventing both reflex and volitional signals from being able to actuate muscles. Muscles triggered by an external (shock) current will involuntarily contract, and there's nothing the victim can do about it.
This problem is especially dangerous if the victim contacts an energized conductor with his or her hands. The forearm muscles responsible for bending fingers tend to be better developed than those muscles responsible for extending fingers, and so if both sets of muscles try to contract because of an electric current conducted through the person's arm, the "bending" muscles will win, clenching the fingers into a fist. If the conductor delivering current to the victim faces the palm of his or her hand, this clenching action will force the hand to grasp the wire firmly, thus worsening the situation by securing excellent contact with the wire. The victim will be completely unable to let go of the wire.
Medically, this condition of involuntary muscle contraction is called tetanus. Electricians familiar with this effect of electric shock often refer to an immobilized victim of electric shock as being "froze on the circuit." Shock-induced tetanus can only be interrupted by stopping the current through the victim.
Even when the current is stopped, the victim may not regain voluntary control over their muscles for a while, as the neurotransmitter chemistry has been thrown into disarray. This principle has been applied in "stun gun" devices such as Tasers, which on the principle of momentarily shocking a victim with a high-voltage pulse delivered between two electrodes. A well-placed shock has the effect of temporarily (a few minutes) immobilizing the victim.
Electric current is able to affect more than just skeletal muscles in a shock victim, however. The diaphragm muscle controlling the lungs, and the heart, which is a muscle in itself, can also be "frozen" in a state of tetanus by electric current. Even currents too low to induce tetanus are often able to scramble nerve cell signals enough that the heart cannot beat properly, sending the heart into a condition known as fibrillation. A fibrillating heart flutters rather than beats, and is ineffective at pumping blood to vital organs in the body. In any case, death from asphyxiation and/or cardiac arrest will surely result from a strong enough electric current through the body. Ironically, medical personnel use a strong jolt of electric current applied across the chest of a victim to "jump start" a fibrillating heart into a normal beating pattern.
A common phrase heard in reference to electrical safety goes something like this: "It's not voltage that kills, it's current!" While there is an element of truth to this, there's more to understand about shock hazard than this simple adage. If voltage presented no danger, no one would ever print and display signs saying : DANGER - HIGH VOLTAGE!
The principle that current kills is essentially correct. It is an electric current that burns tissue, freezes muscles, and fibrillates hearts. However, electric current doesn't just occur on it's own: there must be voltage available to motivate electrons through a victim. A person's body also presents resistance to current, which must be taken into account.
The amount of current through a body is equal to the amount of voltage applied between two points on that body, divided by the electrical resistance offered by the body between those two points. Obviously, the more voltage available to cause electrons to flow, the easier they will flow through any given amount of resistance. Hence, the danger of high voltage: high voltage means potential for large amounts of current through your body, which will injure or kill you. Conversely, the more resistance a body offers to current, the slower electrons will flow for any given amount of voltage. Just how much voltage is dangerous depends on how much total resistance is in the circuit to oppose the flow of electrons.
Body resistance is not a fixed quantity. It varies from person to person and from time to time. There's even a body fat measurement technique based on a measurement of electrical resistance between a person's toes and ¯ngers. DiŽering percentages of body fat give provide diŽerent resistances: just one variable affecting electrical resistance in the human body. In order for the technique to work accurately, the person must regulate their °uid intake for several hours prior to the test, indicating that body hydration another factor impacting the body's electrical resistance. Body resistance also varies depending on how contact is made with the skin: is it from hand-to-hand, hand-to-foot, foot-to-foot, hand-to-elbow, etc.? Sweat, being rich in salts and minerals, is an excellent conductor of electricity for being a liquid. So is blood, with its similarly high content of conductive chemicals. Thus, contact with a wire made by a sweaty hand or open wound will offer much less resistance to current than contact made by clean, dry skin.
But how much current is harmful? The answer to that question also depends on several factors. Individual body chemistry has a signifcant impact on how electric current affects an individual.Some people are highly sensitive to current, experiencing involuntary muscle contraction with shocks from static electricity. Others can draw large sparks from discharging static electricity and hardly feel it, much less experience a muscle spasm. Despite these differences, approximate guidelines have been developed through tests which indicate very little current being necessary to manifest harmful effects.
Keep in mind that these figures are only approximate, as individuals with different body chemistry may react differently. It has been suggested that an across-the-chest current of only 17 milliamps AC is enough to induce fibrillation in a human subject under certain conditions. Most of our data regarding induced fibrillation comes from animal testing. Obviously, it is not practical to perform tests of induced ventricular fibrillation on human subjects, so the available data is sketchy. Oh, and in case you're wondering, I have no idea why women tend to be more susceptible to electric currents than men! |
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| faithblinded |
So for example, let's say that in an average, dry handed state, my body presents 1 million Ohm's of resistance from hand to hand, when I hold the probes of my multimeter, one in each hand. Now for some Ohm's law.
If I take 110V, Ohm's law states that I will recieve .11 mA of current. (current = voltage divided by resistance) Slight tingle at this point.
At 220V, I will receive .22 mA of current. Definitely can feel it now, but not intolerable.
At 1000V, I will recieve 1 mA of current. Might hurt a little at this point, but I might be able to let go.
At 10,000V I would receive 10 mA of current. A wee bit painful and a good chance of not being able to let go.
Now, let's say my hands are wet. What is my resistance now when I measure it on my meter? 17 thousand Ohm's this time, way below the 1 million Ohm's when my hands were dry and clean(optimal). Let's use the same voltages and see what happens now.
At 110V I would take 6.5 mA or so. MUCH worse than before. I can feel it, but I can still let go probably. Hurts a lil though.
At 220V I take about 12.9 mA. WAY worse than dry hands. Might not be able to let go.
At 1000V I take 58.9 mA. Whoah, getting dangerous here. This is gonna hurt a bit. Not sure if I could let go.
At 10,000V I'd take 588 mA. Seriously lethal here. My chances are slim. Probable fibrillation of my ticker.
Sorry for that total rant. Just wanted to help people gain a better understanding of the dangers of electricity and what it can do to you. I tried to keep my quote from that book as short as possible. It's a good textbook, easy to follow, if anyone is interested in getting into serious electronics I think it's a decent starting place. Maybe this should become a permanent safety thread. Not that there aren't enough permanent threads already though... |
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| faithblinded |
hmm maybe that's a little off topic. Maybe an Op could move these last 3 posts of mine to a new thread entitled "The Dangers of Electricity" or some such. I'm going to write up a similar thread at the builder group...
thanks... |
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| ace3000_1 |
| quote: | Originally posted by faithblinded
So for example, let's say that in an average, dry handed state, my body presents 1 million Ohm's of resistance from hand to hand, when I hold the probes of my multimeter, one in each hand. Now for some Ohm's law.
If I take 110V, Ohm's law states that I will recieve .11 mA of current. (current = voltage divided by resistance) Slight tingle at this point.
At 220V, I will receive .22 mA of current. Definitely can feel it now, but not intolerable.
At 1000V, I will recieve 1 mA of current. Might hurt a little at this point, but I might be able to let go.
At 10,000V I would receive 10 mA of current. A wee bit painful and a good chance of not being able to let go.
Now, let's say my hands are wet. What is my resistance now when I measure it on my meter? 17 thousand Ohm's this time, way below the 1 million Ohm's when my hands were dry and clean(optimal). Let's use the same voltages and see what happens now.
At 110V I would take 6.5 mA or so. MUCH worse than before. I can feel it, but I can still let go probably. Hurts a lil though.
At 220V I take about 12.9 mA. WAY worse than dry hands. Might not be able to let go.
At 1000V I take 58.9 mA. Whoah, getting dangerous here. This is gonna hurt a bit. Not sure if I could let go.
At 10,000V I'd take 588 mA. Seriously lethal here. My chances are slim. Total vefribulation.
Sorry for that total rant. Just wanted to help people gain a better understanding of the dangers of electricity and what it can do to you. I tried to keep my quote from that book as short as possible. It's a good textbook, easy to follow, if anyone is interested in getting into serious electronics I think it's a decent starting place. Maybe this should become a permanent safety thread. Not that there aren't enough permanent threads already though... |
That sound about right, when i got the shock from the cap though i didnt get a real big pain but i couldnt let go lol, put it this way it was enough power to go from my 2 fingers to my head within milliseconds. How did i know it was over 400v? well after the boot i turned on the faulty power supply and measured the cap and discharged it acordingly, (typical with a analog multimeter), the cap wasnt discharging because of a broken track on the psu, even with that said they will still hold power with no load.
Faith i wasnt arguing with you before or doubting your knewlege, that post wasnt so good for the best part as i was half asleep when i made that post:).
As for high voltage being a risk, well we only have to look at electric fences and thier specs for the amount of current they run to sting a large animal that has even a higher resistance then humans, also car spark pluggs typically run on next to no amps, but take a look at the spark!
Another small thing im going to mention in here is dont think power cant go through insulated cable, because it can, dont even think about grasping an insulated cable, ( i soon learnt that from working on cars as spark plugg leads can hurt lol). Electricity will always flow to an easier path, ( the old saying goes with electronics, think in the flow as if it was water), and if you are that easier path, look out.
And thats one reason why you should always use the corect cable, ie: higher the voltage, the thicker the insulation, the higher the current draw, the thicker the center cable, then there is also heat in which the cable insulation is made from certain materials to handle the heat. Take a look at the fc2 socket cable, its silicon, its thick insulation and the wires are relativly thin, normal mains wires in that kind of configeration is not aceptible, maybe for the current, but not for the heat nor the insulating factor, these cables have to be double insulated!, and must be able to take over a temp of 350deg c. normal mains wires are normally upto between 60deg c to 90deg c, i think you can figure the rest out on your own on what would happen down the track.
Trev |
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| faithblinded |
| Heh I wasn't arguing this thread just gave me an urge to rant. I find all of this very interesting and I wanted to share. The bit from that book I thought was particularly interesting. I'm a collector of ecclectic knowledge, and jump at opportunities to spew it relevantly. Heh I love jeopardy. |
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| bobharry |
| Sounds right to me too;), I tried to give an example and I knew it wouldn't be accurate, but I didn't know how innaccurate it would be. |
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| ashok |
I think we can never say enough about this and people STILL get shocked . We always get away with it but some people just get 'caught' with catastrophic results.
Quote : "It has been suggested that an across-the-chest current of only 17 milliamps AC is enough to induce fibrillation in a human subject under certain conditions...."
A cousin of mine accidentally touched the unshielded pins of an extension plug and socket. He got shocked between two thumbs , just for an instant . Killed his heart instantly !! He got up sat on a chair and collapsed. His brain activity supposedly went on for three minutes before he died. He lost muscle activity about 30 seconds after he sat on the chair. So he KNEW what was happening for nearly 2 minutes befor he died but couldn't let anyone know what was going on in his mind !
Don't let his happen to you . Maybe being over careful is better than being careless. You don't suffer much , all the others around you do ..............sometimes for their whole lifetime ! |
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| bboyquick |
my friend said his baby cousin shoved a fork into a socket caught on fire and burned to death....
true story. |
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| karma |
true story.
10 years back my friend had this microwave that had no power
so i went to his house to have a look at it thinking it was a fuze.
got there . i have the lid off i replace the fuze. and it was unplugged;) and the main cap was uncharged. anyway i had my hand on the transformer that was not grounded the dude plugs it in when im working on it:rolleyes:
all i remember is geting off the floor and the smell of burning
flesh. left hand left foot was burned.
but some how i lived. to bad he didnt he was killed burned a hole in his hand
and i took all the Precautions he was there just in case i was shocked
one of manny microwaves i have fixed and the last
!! 3000 to 5000 volts DC and higher! !
:( |
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