Guest anguscanplay Posted November 8, 2007 Share Posted November 8, 2007 during an alarm service last night I tested the 240v and got the following L - N 240v N - E 170v L - E 70v obviously adviced the customer to get an electrition(sic) in as a matter of urgency (ie straightaway) what could have been wrong? and should I have powered them down? Link to comment Share on other sites More sharing options...
luggsey Posted November 8, 2007 Share Posted November 8, 2007 during an alarm service last night I tested the 240v and got the followingL - N 240v N - E 170v L - E 70v obviously adviced the customer to get an electrition(sic) in as a matter of urgency (ie straightaway) what could have been wrong? and should I have powered them down? I suspect there was a neutral earth fault there, was the earthing TT (Earth stake) or TNCS (PME) ? Either way there was potential on the earth which is dangerous, if you are not a sparks I would think your actions were correct but I would have powered down the offending circuit "just in case" and put it firmly back in the customers court as it were. I did a little job for a friend a while ago, just looked at a faulty shower for him. I always have a peek at the mains board before I go and found a DB with no cover and exposed buzz bars, my friend was totally unfazed by this and said nobody touched it anyway!!!! That's a 100A killer if you touch it but he still wasn't worried!! Some people..... ----------------------------------------------------------------------------------------------------------------------------------- Life is like a box of chocolates, some bugger always gets the nice ones! My Amateur Radio Forum Link to comment Share on other sites More sharing options...
arfur mo Posted November 8, 2007 Share Posted November 8, 2007 I suspect there was a neutral earth fault there, was the earthing TT (Earth stake) or TNCS (PME) ? Either way there was potential on the earth which is dangerous, if you are not a sparks I would think your actions were correct but I would have powered down the offending circuit "just in case" and put it firmly back in the customers court as it were. I did a little job for a friend a while ago, just looked at a faulty shower for him. I always have a peek at the mains board before I go and found a DB with no cover and exposed buzz bars, my friend was totally unfazed by this and said nobody touched it anyway!!!! That's a 100A killer if you touch it but he still wasn't worried!! Some people..... had similar experiences when i've collected a 'belt' of a neutral side of a control power block, not at full power but enough to make you hop a bit and swear a lot. a sparks i asked about this said, it can be down to high power being drawn (say an electric fire), which is far (electrically) away from the incoming supply or via a high resistance connection. current that go's out must come back, so some of it will go through you if your bit of wire you touching is also near the power draining devices. the neutral is eventually joined to the earth point, and earth is a return path to the power station hence you cop a shock. seemed to make sense at the time to me - if not now , not sure i have explained the theory properly was a while ago, either way such circumstances need sorting out promptly. regs alan If you think education is difficult, try being stupid!!!! Link to comment Share on other sites More sharing options...
markovitch Posted November 8, 2007 Share Posted November 8, 2007 during an alarm service last night I tested the 240v and got the followingL - N 240v N - E 170v L - E 70v obviously adviced the customer to get an electrition(sic) in as a matter of urgency (ie straightaway) what could have been wrong? and should I have powered them down? Something weird going on there,i would of powered it down for safety reasons Angus .Should'nt it of tripped the rcd Angus? Link to comment Share on other sites More sharing options...
Guest anguscanplay Posted November 8, 2007 Share Posted November 8, 2007 thanks Luggsy- seems I was right to power it down then, though obviously the customer didn`t see it that way Link to comment Share on other sites More sharing options...
barooga Posted November 8, 2007 Share Posted November 8, 2007 Something weird going on there,i would of powered it down for safety reasons Angus .Should'nt it of tripped the rcd Angus? As luggsey says, Earth-Neutral leak. Can often be a simple cause such as the screws catching the live wire when fitting the spur/sockets. Regarding the RCD, may not be one. Growing old is mandatory, growing up is optional Link to comment Share on other sites More sharing options...
breff Posted November 8, 2007 Share Posted November 8, 2007 I had the same thing about a week ago, I tested a socket and that was fine so I traced back to a water heater spur that our spur came off and found the earth had come unconnected. I reconnected it and then it was all ok. Weird though because I would have expected 0v between earth and neutral or live. I wondered if it was due to being a metal panel and it possibly earthing partially through the wall. The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not) Link to comment Share on other sites More sharing options...
amateurandy Posted November 8, 2007 Share Posted November 8, 2007 I had the same thing about a week ago, I tested a socket and that was fine so I traced back to a water heater spur that our spur came off and found the earth had come unconnected. I reconnected it and then it was all ok. Weird though because I would have expected 0v between earth and neutral or live. I wondered if it was due to being a metal panel and it possibly earthing partially through the wall. If the earth was disconnected and the cable was in use (under load) I guess there could be some induced AC in the "floating" earth core - don't know how much that could "potentially" be though. Link to comment Share on other sites More sharing options...
arfur mo Posted November 8, 2007 Share Posted November 8, 2007 I had the same thing about a week ago, I tested a socket and that was fine so I traced back to a water heater spur that our spur came off and found the earth had come unconnected. I reconnected it and then it was all ok. Weird though because I would have expected 0v between earth and neutral or live. I wondered if it was due to being a metal panel and it possibly earthing partially through the wall. sorry bref, i just had to point out imo that's bad news, the 'noise' from the element and stat switching it is severe, and just asking for problems. i'm not sure if it is even 'legal' either unless the spur is fed from the same size cable as feeds the immersion heater outlet. regs alan If you think education is difficult, try being stupid!!!! Link to comment Share on other sites More sharing options...
Guest anguscanplay Posted November 8, 2007 Share Posted November 8, 2007 I had the same thing about a week ago, I tested a socket and that was fine so I traced back to a water heater spur that our spur came off and found the earth had come unconnected. I reconnected it and then it was all ok. Weird though because I would have expected 0v between earth and neutral or live. I wondered if it was due to being a metal panel and it possibly earthing partially through the wall. is that a spur OFF a spur ? Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.