sjsturner Posted June 3, 2013 Share Posted June 3, 2013 Yep - the small purple sockets are for inspection lamps. You'll see them on large machinery in quarries etc. as well. I have seen them in hospital plant rooms too Link to comment Share on other sites More sharing options...
cybergibbons Posted June 3, 2013 Share Posted June 3, 2013 I really don't think there is any argument for doing anything but a decent test for isolation. There are a lot of accidents every year where people don't do it properly and get hurt. Non-contact voltage detectors shouldn't be sold to homeowners. Same with those £3 multimeters that claim they are safe for mains voltages. Same with neons. I used to love using a Fluke Volt-alert for tracing out problems in PLC panels. Quicker and safer that poking round with a meter. I'm a big fan of Fluke voltage testers for people who only know a bit about what they are doing though. Removing the capability to measure current makes ****-ups much harder. I don't see the value in testing with multiple, progressively less safe, devices. If the neon isn't CATII or CATIII, don't use it for testing. I have a blog, some of which is about alarm security and reverse engineering:http://cybergibbons.com/ Link to comment Share on other sites More sharing options...
datadiffusion Posted June 3, 2013 Share Posted June 3, 2013 I thought it was 50ma for cardiac arrest But yes we do use 30 Like james said, its the current that will kill you. Im suprised arf didnt know these things after all these years, but then again i learnt this on spark course Have to say as the number of older installations with RCDs increases, and some are now 15-20 years old, I am constantly finding ones that do not trip when I'm doing my minor works certs. Can't believe some people don't understand the basic concept of Centre Tapped 110V though. So, I've decided to take my work back underground.... to stop it falling into the wrong hands Link to comment Share on other sites More sharing options...
MrHappy Posted June 3, 2013 Share Posted June 3, 2013 Can't believe some people don't understand the basic concept of Centre Tapped 110V though. TBH I was going to get a tranformer out the stores & measure, then the phones started to ring... Mr Veritas God Link to comment Share on other sites More sharing options...
datadiffusion Posted June 3, 2013 Share Posted June 3, 2013 You'll have to cut it in half to be sure.... So, I've decided to take my work back underground.... to stop it falling into the wrong hands Link to comment Share on other sites More sharing options...
bee_man Posted June 3, 2013 Share Posted June 3, 2013 > belt from between 80 and 150 ac can be unpleasant but is not as dangerous. Depends entirely on circumstances. A person has been killed by 32V and another person survived 220kV. I wouldn't like to generalise, but it would be interesting to see how many Americans are killed by 110VAC. Electrocution depends on current much more than it does voltage. It also depends on skin resistance, humidity and especially frequency. Heart muscle response time is about 3mS, so get near the resonant frequency of that and I would a few volts would see you in trouble. It's a much more complicated subject than meets the eye. I've had phase to phase hand to hand and walked away without a flinch. I've also had single phase hand to foot/earth and jumped about and swore loudly. > if so, the neon because it will indicate from below to 500 volts, is highly reliable at warning of a possible > (i.e. higher) dangerous voltage potential? Can I assume we are talking about a neon indicator which has just the spike probe, no other wires?. That's how they were when I last saw one. In that case, to answer your question, you'd have to ask "where does the return current go". The only way I can see it working is by cacpacitive coupling to you, ie the return current goes through you to earth. So at the instant of peak voltage on the AC cycle I lift the probe and very quickly touch it on earth. The capacitance must hold that peak voltage for a while, and we just earthed the bit that was charged to +400V, so what part of the probe or you gets to see the -400V spike? I dunno, some people like them, but I wouldn't recommend anybody use a probe to measure 400+ volts when they form part of the current path. bee Link to comment Share on other sites More sharing options...
Cubit Posted June 3, 2013 Share Posted June 3, 2013 Bee Man. Just a heads up on this. The topic comes round regularly and always by the same eejit. All the sparkies are wrong because the witless one says so. Link to comment Share on other sites More sharing options...
Oxo Posted June 3, 2013 Share Posted June 3, 2013 lol Link to comment Share on other sites More sharing options...
arfur mo Posted June 4, 2013 Share Posted June 4, 2013 The 110 as stated is single phase and is 110 v rms. 55-0-55 so at any one time the full voltage is 55 above or below earth. its the volts that jolts, its the mills that kills great informative but whats the point in reference to this thread? as said, i do not care what voltage is outside my home, only the voltage that comes within it. how it is dropped from thousands of volts to 240 is not exactly going to float my bat either. my 3 yellow trannie's and when on site i'v only ever been offered 110, never yet ever seen 25 or 55 options, and have nothing that works off it either., so never looked hard. i won't go anywhere near 415 - even with my gold laminated neon thank you. might be theses days like most, i mainly use cordless everywhere far safer, independent and instead of fighting for sockets and having extension leads borrowed aka nicked.. Yep - the small purple sockets are for inspection lamps. You'll see them on large machinery in quarries etc. as well. having never worked in quarries is likely why i am not alone to have no interest. If you think education is difficult, try being stupid!!!! Link to comment Share on other sites More sharing options...
arfur mo Posted June 4, 2013 Share Posted June 4, 2013 Bee Man. Just a heads up on this. The topic comes round regularly and always by the same eejit. All the sparkies are wrong because the witless one says so. not quit correct, as always we had a poster asking about his system problems, was told to check/replace his battery no mention of any safety precautions. having been a victim of many sparks mis wires i told him to make double sure the power was off by testing with a neon. this remark designed to say be careful, don't trust the fused outlet to disconnect the live. it sparked a near all out disproval war, comments like 'if my instructor see me using one....' about using approved equipment to test (like the average house will have this), better to use a meter ( like the average engineer can even use one - let alone safely as widely demonstrated by the incredible ignorance about proper and repeat testing meter leads earlier). i asked for any fatalities recorded as a cause by use of a neon screwdrivers. fair question i feel, given billy billions have been made, come in many screwdriver sets, sold in sheds as well as all electrical wholesalers - i'd bet most households have one if not several - even Cubits. yet not one was put up, the only one i found was a guy in America had decided to check some power while stark bullock naked, got a tingle on his toggle when it touched a metal table with it at the same. one young man lad posted his engineer had got a shock from a neon after being handed a neon brought from his van, it was dropped in a puddle en-route, engineer was not told of this accident. now i ask, would any electrical engineer offer a wet test device to a live mains? sorry - Que. Cubit! back to our man and his alarm, if he had other test kit like a £5 boot sale meter with then he would likely use it, possibly get the wrong so dangerous diagnosis and be dead on the floor, short of soaking your neon in a bath, i claim evidence for this device safety by means of lack of recorded instances, was a safer bet than any meter in the wrong hands, calibrated, block tested or otherwise. if they are so dangerous by design as either a primary or secondary test then show the cast iron evidence - not supposition - simple as If you think education is difficult, try being stupid!!!! Link to comment Share on other sites More sharing options...
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