amateurandy Posted September 19, 2007 Share Posted September 19, 2007 Double pole is electricially safer if the earthing is TT where neutral potential can rise and fall (Up to 240v!).If the installation is PME/TNCS etc then the neutral potential is clamped at earth potential so double pole is not really useful, if you think about it having single pole isolation on a PME/TNCS installation may be safer as there are two conductors at eart potential...... Hi Luggsey, This may be straying a bit from the original topic, but as I don't know what TT and PME/TNCS stand for please bear with me..... My house power supply is overhead wires and the Electricity Company engineers told me a while back (while re-establishing and verifying the Earth connection) that Earth is clamped to Neutral and that every alternate pole has a conductor linking neutral to the "real earth". Does this have any implications for wiring in my house? Incidentally I do actually have some DP switches, it sounds like they may be overkill.... Link to comment Share on other sites More sharing options...
luggsey Posted September 19, 2007 Share Posted September 19, 2007 Hi Luggsey,This may be straying a bit from the original topic, but as I don't know what TT and PME/TNCS stand for please bear with me..... My house power supply is overhead wires and the Electricity Company engineers told me a while back (while re-establishing and verifying the Earth connection) that Earth is clamped to Neutral and that every alternate pole has a conductor linking neutral to the "real earth". Does this have any implications for wiring in my house? Incidentally I do actually have some DP switches, it sounds like they may be overkill.... Just that the PME system is generally safer IMO, there are occasions when PME causes problems, (broken neutral on suppliers side causing earth potential to rise, nasty) but on the whole it's better. ----------------------------------------------------------------------------------------------------------------------------------- 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...
amateurandy Posted September 19, 2007 Share Posted September 19, 2007 Just that the PME system is generally safer IMO, there are occasions when PME causes problems, (broken neutral on suppliers side causing earth potential to rise, nasty) but on the whole it's better. OK, looked it up, PME = Protective Multiple Earthing. Unfortunately my house was built in 1967 and there's probably no consistent bonding of the various metal items in it... I'm absolutely certain for instance that neither of my 2 steel enamelled baths are specifically earthed. I think the incoming water main is also still linked up (it was the original earth) but the header tanks are all plastic so the internal plumbing (all copper) is probably not well earthed either - it maybe has some indirect connection via the kitchen sink! But that will depend on how the taps are fitted to it - washers etc. As for the gas supply, I wouldn't have a clue. Should I be worried? PS Oddly enough the first useful source I found of this info was on an amateur radio site.... Link to comment Share on other sites More sharing options...
Guest G.J.M Posted September 19, 2007 Share Posted September 19, 2007 , just that the skilled sparks will have a better idea of electricial safety, installation methods and wiring zones etc. yet to see it myself Link to comment Share on other sites More sharing options...
luggsey Posted September 19, 2007 Share Posted September 19, 2007 OK, looked it up, PME = Protective Multiple Earthing.Unfortunately my house was built in 1967 and there's probably no consistent bonding of the various metal items in it...I'm absolutely certain for instance that neither of my 2 steel enamelled baths are specifically earthed.I think the incoming water main is also still linked up (it was the original earth) but the header tanks are all plastic so the internal plumbing (all copper) is probably not well earthed either - it maybe has some indirect connection via the kitchen sink! But that will depend on how the taps are fitted to it - washers etc.As for the gas supply, I wouldn't have a clue.Should I be worried?PS Oddly enough the first useful source I found of this info was on an amateur radio site....Sounds like you need your "bonding" upgraded Andy, do it yourself if you have the ability?The bathroom and the kitchen are "special locations" and as such require a registered sparks to sign off on the work but that's up to you!Are you an amateur Andy? See my sig file.Paul.yet to see it myselfI did say "skilled" sparks......not the pretenders that play with t&e all day..... ----------------------------------------------------------------------------------------------------------------------------------- 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...
amateurandy Posted September 19, 2007 Share Posted September 19, 2007 Sounds like you need your "bonding" upgraded Andy, do it yourself if you have the ability?The bathroom and the kitchen are "special locations" and as such require a registered sparks to sign off on the work but that's up to you!Are you an amateur Andy? See my sig file.Paul. Many thanks. Let's just say I've done plenty of rewiring in this house over the years but never looked specifically at the "bonding". And Part P has been done to death elsewhere so I won't start that again No, not into radio (just computers and networks) but it just happened that Googling PME led me first to www.rsgb.org and I also saw your signature. Isn't Dave (Service Engineer) into radio as well? Link to comment Share on other sites More sharing options...
morph Posted September 19, 2007 Share Posted September 19, 2007 Many thanks. Let's just say I've done plenty of rewiring in this house over the years but never looked specifically at the "bonding". And Part P has been done to death elsewhere so I won't start that again No, not into radio (just computers and networks) but it just happened that Googling PME led me first to www.rsgb.org and I also saw your signature. Isn't Dave (Service Engineer) into radio as well? Theres a few Radio Amateurs on the forums. Link to comment Share on other sites More sharing options...
Guest Cerberus NI Posted September 19, 2007 Share Posted September 19, 2007 I think that the original topic has been covered and conclusions drawn Link to comment Share on other sites More sharing options...
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