Gyn_Paul Posted February 21, 2008 Share Posted February 21, 2008 The earth wire from my telephone junction box ambles through a doorway to the usual sort of installation which FT seem to think constitutes a good earth (a bit of galvanized pipe with the wire stuffed under some sort of U-clamp).This is the doorway which I'm preping for a new front door. I've got to move the junction box a couple of centimeters anyway, and since my new extra-long earth spike for the second electricity tableau is close to hand, it seems logical to transfer the FT earth wire to that (probably a damn-sight lower resistance than the rusty pipe it's currently nearly attached to!).I'm sure there's a regulation which forbids this, but I'm wondering if Punch (or anyone else who might care to hazard an opinion) can explain why....p Link to comment Share on other sites More sharing options...
Gyn_Paul Posted February 22, 2008 Author Share Posted February 22, 2008 Wot, no electrician with an opinion ???p Link to comment Share on other sites More sharing options...
Nick Trollope Posted February 23, 2008 Share Posted February 23, 2008 [quote user="Gyn_Paul"]Wot, no electrician with an opinion ???p[/quote]Nope. I haven't seen an earth on a telephone line since the 70's.I don't believe that one can share earths at all... Link to comment Share on other sites More sharing options...
Gyn_Paul Posted February 23, 2008 Author Share Posted February 23, 2008 Well judging by the cream colour of the junction box and the state of the drop-wire, I'd say this was put in in the '90s. Perhaps they are a function of rural installations with 100% o/h cabling ?p Link to comment Share on other sites More sharing options...
AnOther Posted February 23, 2008 Share Posted February 23, 2008 Is it even connected to anything ?All you need is a single pair neither of which is, or should be, connected to ground.Earth wires in telephone cables are a redundant and a legacy from the pulse dialling systems of yesteryear.I have one coming into my house and it snakes across the pathway beside the house. When I asked the French lady from whom we bought about it she was at great pains to stress that it was vital and should be taken care of but in reality it was of course connected to nowt ! Link to comment Share on other sites More sharing options...
Gluestick Posted February 23, 2008 Share Posted February 23, 2008 Same thought had ocurred to me GP.Why not try disconnecting it and if the phone still works........................then it's out with the cable cutters! Link to comment Share on other sites More sharing options...
Punch Posted February 23, 2008 Share Posted February 23, 2008 The only earth entering and leaving the "barrette de terre" and main earth rod of an installation should be the main earthing cable for the electrical installation itself. The telephone incoming "test" socket situated in the GTL of new installations has to be earthed with a minimum 4mm size earth wire to the tableau electrique main earth bar. Older installations usually have a earth wire directly into the ground somewhere (as stated earlier in this thread)I believe these earths are for lightning protection purposes. www.punchardrenovation.com Link to comment Share on other sites More sharing options...
Gyn_Paul Posted February 23, 2008 Author Share Posted February 23, 2008 [quote user="Punch"]The only earth entering and leaving the "barrette de terre" and main earth rod of an installation should be the main earthing cable for the electrical installation itself. The telephone incoming "test" socket situated in the GTL of new installations has to be earthed with a minimum 4mm size earth wire to the tableau electrique main earth bar. Older installations usually have a earth wire directly into the ground somewhere (as stated earlier in this thread)I believe these earths are for lightning protection purposes. www.punchardrenovation.com [/quote]Let me see if I've got this right:If the phone line, junction box, cabling etc are separate, then it's interdit to connect its earth wire to the same spike as the electric tableau, because that would mean they are effectively sharing a path to earth.Unless of course the telephone wiring (etc) and the phone test socket are co-sited with the electrical tableau (I'm assuming a GTL is that plastic extrusion below a pre-formed tableau-and-trunking setup which seems to cost more than the tableau and all the disjoncteur put together) in which case it's quite OK to connect it to the tableau's earth (and ultimately the same spike).Aren't these two scenaria electrically the same?Is this right ?Is this French?Is it any wonder I'm confused? [8-)]As a sidebar I note that the sheds are still selling these things (I'll call them a GTL until someone puts me right) with the usual FT inverted 'T' socket. I understood that the norm from 1 jan 2008 was an RJ45 socket.p Link to comment Share on other sites More sharing options...
Chancer Posted February 23, 2008 Share Posted February 23, 2008 My Consuel inspector asked me to connect the barrette de terre in the GTL (actually I used a tableau nu) to the one in the main tableau, which I did while he was there, he did not ask me to then connect it to the telephone master/test socket which in any case I dont think has an earth terminal.EdittedIt is permissable to connect more than one main earthing cable to an earth spike for a multiple installation, I will have in total 7 different metered supplies to apartments that will all share the same picqet de terre.The consuel guy confirmed that this is OK and it of course cuts down on the testing, I think the rational is that it is highly unlikely that more than one installation will be carrying a fault current simultaneously given that each DD would trip within 30ms. Link to comment Share on other sites More sharing options...
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