condorman Posted August 4, 2009 Share Posted August 4, 2009 Hi, Question for a sparky please. I have a 3 phaze supply to my house, I have noticed a burningtingling sensation from touching the metal parts on my computer case,even a mild mild shock like from a tens machine. I have mcbs in theconsumer unit. I have noticed that when it rains heavilly there is noshock sensation or much less, this may be a red herring but i'm quitesure of it. Any ideas please on what the cause of this may be? I'mthinking ( due to the rain) that it may have something to do with thehigh ground resistance when dry and when wet the ground works better.There is a 1 meter copper rod burried in the ground. Although if thisis the case should this be happening? is this earth leakage? Thank youin advance for any ideas on the cause. Think ill try it on some othercircuits tomorow to see if it's on all or just on the 1. Thank you. Link to comment Share on other sites More sharing options...
condorman Posted August 4, 2009 Author Share Posted August 4, 2009 Update... Update..... Just put one of those neon testers on the metal computer case and it glows bright, if i then touch the wall with the other hand it goes dim. Link to comment Share on other sites More sharing options...
Dave&Olive Posted August 4, 2009 Share Posted August 4, 2009 hi ok Will tell you a tale ...friend of mine had a UK reg spark put in some new sockets in for him . All worked well for 2 years then he asked me to move his washing machine from the kitchen to the boiler room ..done all the plumbing for him and he plugged it to a socket that had been put in by the above spark and bang ..one dead washer . I then find out his wife had been getting tingling shocks from the f/freezer for 2 years so got out my trusty meter ... results live -neutral 220 volts....neutral - earth 220 volts earth-live 440 volts . What the bright spark had done ... he had taken the feed from a 3 phase cable running to the barn this was 4 core cable brown-phase, black phase ,blue-neutral ,and earth y/green .....but the earth was not an earth but the 3rd phase ... everything was ok until you plugged in something with an earth on it . get it checked PDQ Dave Link to comment Share on other sites More sharing options...
Anton Redman Posted August 4, 2009 Share Posted August 4, 2009 Do not play about. Sort it out so there is no tingling. Probably turn off every circuit then turn them on one at a time and find out where the problem is. Link to comment Share on other sites More sharing options...
condorman Posted August 4, 2009 Author Share Posted August 4, 2009 Hi Guys, Thank you for the replies. I found the fault on the lounge circuit, then thought it was a multi gang trailing socket but it turns out the problem was gone when i removed the uk/france travel adaptor. I've now put French plugs on everything and it is all fine. Thanks Dave for that info, Ill look into changing the 3 phaze . I noticed 2 metal framed fluorescent lights that have no earth are showing live on the casing but still work fine so think ill need to look into it and it sounds like what you are saying Dave. Thanks Guys. Link to comment Share on other sites More sharing options...
Dog Posted August 4, 2009 Share Posted August 4, 2009 It's an earth problem - not the end of the world - get it fixed/ Link to comment Share on other sites More sharing options...
Dave&Olive Posted August 5, 2009 Share Posted August 5, 2009 [quote user="Dog"]It's an earth problem - not the end of the world - get it fixed/[/quote] must be the best under statment of the year ....IT`s not the end of the world ...just after you have been struck with 440 volts of 3 phase power.....ughhhhhhhhhhhhhhhhh. Dave Link to comment Share on other sites More sharing options...
Gluestick Posted August 5, 2009 Share Posted August 5, 2009 Indeed.It's an "Earth problem" because somehow, mains is leaking through the person touching the case of the PC to earth!Can be poor insulation of a socket, switch, PSU in the PC or at the Tableaux end. Normally caused by the di-electric material suffering tiny surface crazing.Had a similar problem with a 30 Amp switch in a kitchen a few years back: when a microwave was plugged in it was humming: when not in use: and when I touched it, I suffered a distinct "Fizz".It was poor insulation separation of the 30 Amp cooker isolator and the combined 13 Amp socket.Or of course, more seriously, because some bozo has connected a phase to the earth connection in the appliance! Link to comment Share on other sites More sharing options...
AnOther Posted August 5, 2009 Share Posted August 5, 2009 [quote user="condorman"]it turns out the problem was gone when i removed the uk/france travel adaptor.[/quote]I think it's important to note that travel adapters come in 2 distinct types, with earth and without. Most people innocently assume that they all have an earth contact but it's usually very easy to tell if one does or not because if you look you will see that were the earth pins go they actually contact nothing !If you are using any on equipment which should be earthed then you should check them out immediately. The best solution of course is to fit proper French 3 pin plugs [;-)] Link to comment Share on other sites More sharing options...
Dog Posted August 5, 2009 Share Posted August 5, 2009 When I had this problem at my factory the majority of my machines were three phase.One machine if you touched its bare metal gave you a tingle.I had three electricians look at the problem, two ordinary sparkies and a specialist firm.The final explanation I got was to live with it as it was an unusual problem caused between different three phased machines.It carried on tingling for twenty years until I sold up and it still is tingling. Link to comment Share on other sites More sharing options...
Théière Posted August 5, 2009 Share Posted August 5, 2009 I hope you didn't have to pay these "bright Sparks" much, what a lot of Tosh Link to comment Share on other sites More sharing options...
Dog Posted August 5, 2009 Share Posted August 5, 2009 Explain why? I would be pleased to have this problem solved. Link to comment Share on other sites More sharing options...
AnOther Posted August 6, 2009 Share Posted August 6, 2009 Pretty simple and basic I would have thought.If a lump of metal, be it a machine or whatever, is properly earth bonded then there should be no possibility of it carrying a potential hence therefore no tingling. Whether it is 3ph or single makes no odds save for the fact that 3ph of course can be infinitely more deadly under a fault conditon.Your machine then was not (is not) properly or adequately earthed, something which any semi skilled domestic electrician should have been able to diagnose and fix. Link to comment Share on other sites More sharing options...
Théière Posted August 6, 2009 Share Posted August 6, 2009 Thanks Ernie, I really could not be bothered, your explanation was great Link to comment Share on other sites More sharing options...
Dog Posted August 6, 2009 Share Posted August 6, 2009 I can assure you that the machine was adequately earthed. It was another problem that was causing it. Link to comment Share on other sites More sharing options...
Théière Posted August 6, 2009 Share Posted August 6, 2009 Probably one of those rare occasions where the ground has a potential. Link to comment Share on other sites More sharing options...
Cat Posted August 6, 2009 Share Posted August 6, 2009 [quote user="Dog"]I can assure you that the machine was adequately earthed. It was another problem that was causing it.[/quote]Lost neutral or reversed polarity perhaps? Link to comment Share on other sites More sharing options...
Théière Posted August 6, 2009 Share Posted August 6, 2009 If you reverse the polarity on a three phase motor the machine will run in reverse!Can't believe I am debating this nonsense, it's just Dog being his usual Troll self. Link to comment Share on other sites More sharing options...
BIG MAC Posted August 7, 2009 Share Posted August 7, 2009 S'funny I often get a belt when plastering, touching car doors or cheeky to the wife.I didn't know the ground was live...is that why lightning travels upwards then? Link to comment Share on other sites More sharing options...
Théière Posted August 7, 2009 Share Posted August 7, 2009 Hello Big Mac, good trip? Link to comment Share on other sites More sharing options...
BIG MAC Posted August 8, 2009 Share Posted August 8, 2009 Hi Teapot yes indeedy but now going back at the end of the month and October.....I miss the place terribly when not there...it's weird Link to comment Share on other sites More sharing options...
Théière Posted August 8, 2009 Share Posted August 8, 2009 I don't think it's weird, I feel the same. Can't wait until the first week of September [:)] Link to comment Share on other sites More sharing options...
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