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| Thread ID: 21799 | 2002-07-04 05:45:00 | Antistatic Procedures | prism (840) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 59801 | 2002-07-05 12:11:00 | Susan! > potential entertainment for the kids tomorrow - undressing????? :8} The secrets are really coming out tonight! |
Heather P (163) | ||
| 59802 | 2002-07-05 12:17:00 | No need to worry Heather, there's at least another ten layers of thermals underneath the woolly jumper before the kids need to start running.... :-) | Susan B (19) | ||
| 59803 | 2002-07-05 12:31:00 | Hi Bruce I'll write an FAQ for this subject if you like . There is a lot of misinformation in this series of posts, even from the electrically qualified . I hold a current electrical practising licence, have been in the industry for over 35 years and had a hand in structuring the present regulatory environment . Like one other poster (postee?), I too was involved in the trade training area for around 15 years . I modestly suggest that I am uniquely placed to provide advice in this area, and I do not agree that there are liability issues for IDG arising out of advice offered on Press F1 . New Zealand's legislative environment does not encourage such actions . If it did, every home handyman who ever injured himself completing a magazine project, every smoker who ever saw an advertisement, every driver who read a magazine review of a motor vehicle and a heap of similar and equally silly examples would all be queueing up to sue somebody . This is not the US of A (God bless her) and we still believe that people bear some responsibility for the consequnces of their own actions, freely entered into . At most a disclaimer of responsibility, and advice to use a trained and competent technician if in doubt would cover the bases . If you wish to check my bona fides for this exercise Bruce, feel free to contact me on the email address that I submitted with my registration . Cheers Billy 8-{) |
Billy T (70) | ||
| 59804 | 2002-07-05 12:48:00 | A note; it is perfectly OK legally to wire up your own light switches and power points. For a building to have an electrical compliance certificate (say for a building consent) requires a registered electrician. To put a new plug on a toaster (or an antistatic mat) does not. To put that plug on and charge for the service would open you up to massive liability if you were not ticketed in some fashion (and maybe if you were) :-). The earth pin on a plug is the bottom one, with a green wire attached to it. Red = phase, Black = neutral, Green (sometimes G+Yellow)= earth. Running a wire out the window to a metal (preferably copper I expect) rod banged a couple feet into the ground would work. What I dont know is, what sort of mat would be best. Would it need to be conductive or would a plastic (say) mat be good enough? |
Allan (851) | ||
| 59805 | 2002-07-05 13:01:00 | One important point that has been missed by those advising that to leave your pc plugged into the wall socket is best -- What if your wall socket has a faulty switch and/or has been wired up incorrectly and power is still on when the switch is off? If the switch has been incorrectly wired into the neutral wire the appliance will appear to be dead but is in fact very much alive. How many people would have the knowledge or the test meter to be able to test the socket first? Most people think that if the appliance will not operate and the little light won't come on then there must be no power. Wrong--not always true. Be careful guys/gals. | Peter M (852) | ||
| 59806 | 2002-07-05 22:58:00 | ok guys i think you r missing one big point here . . . . . . how many people actually know which pin is earth,neutral and phase? not many i bet . whats a simple safeish optoin? . . . . . . . . . . . . . . . . . leave it plugged in and hope the sparky did his job right . also even if pc is on you won't kill yourself unless you poke something into the powersuppply . if in doubt get a tech to do it . spending a little bit of money beats being dead . |
tweak'e (174) | ||
| 59807 | 2002-07-06 02:54:00 | Well, whilst this has become an interesting discussion, nobody has given one good reason to leave your computer plugged in whilst working on it. I guess the reason is that there is no good reason. (Another myth, like the one of years ago that claimed you can come to no harm if you use a isolating transformer when working with power tools.) To repeat what I previously posted, your safest bet by far is to use all the recommended anti-static practices, but leave the three pin plug to the computer in your pocket. That way you wont need to worry about someone hitting a power pole and mixing up the 11,000 volts with the 230 volts etc. etc. as other posts have pointed out. Neither will you need to worry about litigation. Have a good one Bob |
B.M. (505) | ||
| 59808 | 2002-07-06 03:03:00 | Allan, While it is "perfectly OK legally to wire up your own light switches and power points", it is perfectly illegal to connect them to the mains supply under NZ law (Electricity Act 1992). The homeowner may carry out his or her own wiring, must then test it to be in compliance with ECP 51, and the final connection must be made by a registered electrical inspector - not even an electrician may do this!! It is a popular and dangerous misconception that the householder may connect their own wiring and the penalties for doing so range from a maximum fine of $10,000 to incarceration for manslaughter if someone gets hurt or killed from the installation. By the way, in 1973, the colour codes for flexible cords changed to Brown = Phase (Live, Active), Blue = Neutral and Green/yellow = Earth. If you still have red, black and green flexes then they are getting pretty old and need checking. Anti-static mats are made of a special conductive material so not any old matting will do, and as I said before, should only be connected to earth via a resistor of between 1 megohm and 10 Megohms resistance. Regards, Andy. |
andy (473) | ||
| 59809 | 2002-07-06 04:13:00 | Andy, Could you please explain why I should connect my anti-static mat to earth via a 1 or 10 meg resistor? I'm intrigued. Cheers Bob |
B.M. (505) | ||
| 59810 | 2002-07-06 08:34:00 | Ummm . . . . . . . . Bruce . . . . . . . Sorry, but by discussing the two issues simultaneously, you and many others are mixing electrical safety issues with electro-static protection (for electronic devices) . The two need to be clearly differentiated . Talking about the legislative environment is also a futile exercise as any electrically trained person would know . Just go to your nearest Placemakers or Mitre 10 store of a weekend and watch the mains cables and (to be) permanently-wired electrical appliances or fittings walking out the door . Alternatively, go to Lighting Direct, Lighting Plus, Alpha or any other bulk lighting chain and listen to the wiring advice given, or worse - not given, for light fittings that are not necessarily fully compliant with NZ's legislative requirements and require safety related decisions to be made during installation . Forgetting completely about whether or not you blow your RAM or stuff your CPU, it is quite safe to work on a PC while plugged in to the wall socket, provided the mains switch is off at the power source i . e . the wall outlet . If you are nervous about your safety, pull the appropriate fuse or push the trip button on the relevant circuit breaker . How do you know which one? Plug a radio or other loud noise-making appliance into your computer power socket, turn the sound up a bit then try fuses or breakers one by one till it goes all quiet . Of course all your fuses and/or breakers were supposed to have been labelled by the qualified and competent electrician who installed them, but we won't go down that path! While it would be nice if everybody knew the difference between phase, neutral and earth pins on the plug, the question is largely academic as it makes little practical difference to the safety of the situation, viz: 1) If the wall switch is off, or faulty and stuck in the off position, you can't turn your computer on anyway . End of story . 2) If the wall switch is on, or faulty and stuck in the on position, the computer will still turn on . Test with another appliance if the computer is apparently dead . 3) If neutral and earth are reversed at the wall socket, safety is unaffected as the two conductors are linked at the switchboard . The only practical diference is the colour of the wire . 4) If phase and earth were reversed at the wall socket, the computer would not have worked at all, and nor would any other appliance using that socket . You would almost certainly have experienced a shock long before now while trying to find out why nothing was working off that socket . 5) If phase and neutral are reversed at the wall socket, the computer will still operate normally but things can get interesting if you try and work on the works of the power supply as it will be live internally, regardless of whether the wall switch is off or on . The outer case and associated metalwork of the computer is still earthed however, and the only potentially-exposed live component inside the computer will be one single connector attaching the neutral wire to the on-off power switch . This is provided that the on-off switch switches both phase and neutral (if your computer is old enough to still be switching mains rather than toggling the power supply in and out of electronic shutdown mode) . If your on-off switch is single pole i . e switches one wire only (one wire in, one wire out) then the connector for the wire from the power supply to the switch will be live instead, and is equally dangerous if exposed . Since we are talking solely about electrical safety during replacement of plug-in componemts such as RAM, CPUs, video cards and various other PCI type boards, the risk factor is minimal and I would go so far as to say it is no higher than the daily risks you face using just about any electrical appliance . Statistically you are safer to replace your CPU or add RAM etc with the power plug in the wall (and the main switch off) than you are walking down the street or getting out of your shower, and a heck of a lot safer than driving your car or going out walking after dark . That statement is based on real accident statistics too, as prepared by the Energy Safety Service of the Ministry of Economic Development (formerly the Ministry of Commerce and before that, the Ministry of Electricity) . For other than electrical accidents, refer to ACC and Police statistics . Now, dealing with the original issue, for the average computer user, i . e . the primary constituency of Press F1; talk about antistatic mats, series resistors (10 Meg is fine), earthing and grounding principles and voltages generated by various acts (consenting or otherwise) will just put people off doing simple computer upgrade tasks that they can safely accomplish in the privacy of their own homes . The farthest they are likely to go is to buy an antistatic wrist strap from DSE (Cat X 2042, $21 incl gst . Yes, I have one and use it for longer jobs, but I follow my own advice for simple tasks!) IMHO this thread has contained enough half-truths, urban folk-lore and well-intentioned diversions to put a lot of people right off doing what is a simple, straight forward and safe task . The sole reason for leaving the computer plugged in is to provide a sound and reliable ground reference to eliminate static charges . Mucking about with antistatic bags or throwing wires out of windows is all very well for people who know what they are doing (only they wouldn't engage in such frivolous antics would they? They would go the full nine yards with grounded antistatic mats, wrist straps, Uncle Tom Cobbley and all . I bet!) but for ordinary folk, following the KISS principle is safest and best . Step 1: Turn the computer off, then turn off the switch on the wall socket . Leave the power cord plugged into the wall socket . The computer is now electrically safe to work on, and you can remove the outer case without fear . Step 2: Touching the bare metal case of the power supply or rear panel of the computer will effectively ground you and dissipate any static charges . If your hands are particularly dry, lick a finger first then touch and hold for a few seconds . If you are anything like me though, your hands won't be dry . The thought of buggering my computer through well intentioned bungling is enough to make my hands sweaty every time . Advisory: You are very unlikely to feel any static discharge when you ground yourself, but then you won't feel anything if you forget and zap your RAM or PC card either . [/b] You will, however, feel the pain if you send a stick of RAM to silicon heaven, or worse, damage it just enough to cause intermittent glitches . Step 3: Remove static sensitive device from anti-static wrapping, and hold carefully by edges for RAM/CPU or metal ground plane for PC cards . Touch case again and then insert said device into slot . Close up, repower, enjoy! Further Advisory: If you have to walk anywhere or move about too much after initial grounding, ground yourself again before touching sensitive devices as just a few steps or movements of clothing (especially synthetics) can recharge your person to voltages capable of damaging semiconductors . Just lifting one foot off the floor can induce a damaging static charge and I can assure you that this is a very real possibility because I measure static charges as part of my work . One of my favourite demonstrations is to generate 1,000,000 volts of static electrical charge (yes folks one million volts) with just a few quick rubs of a plastic paddle with a dry cloth . It disappears just as quickly with one touch of a (grounded) finger . Want to change/fit RAM or other PC components? Go for it, just follow common sense electrical safety precautions, and make sure you have discharged your body's static potential before you start . Cheers Billy 8-{) |
Billy T (70) | ||
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