I am attaching a spuron the plugs circuit to add a double plug. This spur will run ..tv..sky box and DVD player. Does the spur wire have to be the same "type" as the the triple earth wire on the circuit ?
Mike P
Are you sure you should be adding a spur when you are asking such a question? The wire you refer to ( It is actually called cable ) is not "triple earth" .It is " twin and earth" ,a live and neutral conductor and a bare earth conductor which should be sleeved in earth sleeving at the connections . The cable will be 2.5mm size so use this size cable for the spur . Have a read here
.. >On Tue, 11 Dec 2007 13:21:25 +0000, Mike P wrote: .. >
.. >>I am attaching a spuron the plugs circuit to add a double plug. This .. >>spur will run ..tv..sky box and DVD player. .. >>Does the spur wire have to be the same "type" as the the triple earth .. >>wire on the circuit ? .. >>
.. >>Mike P .. >
.. >Are you sure you should be adding a spur when you are asking such a .. >question? .. >The wire you refer to ( It is actually called cable ) is not "triple .. >earth" .It is " twin and earth" ,a live and neutral conductor and a .. >bare earth conductor which should be sleeved in earth sleeving at the .. >connections . The cable will be 2.5mm size so use this size cable for .. >the spur . .. >Have a read here .. >
.. >
Thanks ... terminology is a problem for us all. I do sleeve all the earth wires I come across. This is an old house where bare earths are the norm.
Mike P
As a general rule yes but it may be larger.
... >
.. >>
.. >> . The cable will be 2.5mm size so use this size cable for .. >> the spur . .. >> > Stuart .. >
.. >As a general rule yes but it may be larger. .. >
.. >.
The circuit cable is larger. It has 3 coiled earth wires for a start. I spurred off with a 30amp junction box using 2.5mm. Why should the cable all be the same size?
Mike P
On Wed, 12 Dec 2007 08:17:53 +0000 someone who may be Mike P wrote this:-
Personally I would have found out why the cable is larger than expected and how much larger it is.
There are a number of possibilities, a radial socket circuit and someone "borrowing" a circuit that once fed a cooker or shower are the more likely possibilities.
Electric wiring in houses is not always as easy as it appears. An expert is someone who knows how little they know about something. Over-confidence is best avoided with something that can kill, whether by direct means or indirect means like fire.
No matter the bluster about terminology, I agree with Stuart, "Are you sure you should be adding a spur when you are asking such a question?"
It sounds like you've got old cable called 7/0.29. There will be 7 strands of 0.29" twisted together for the live and neutral and 3 of 0.29" for the earth. That is the old standard ring main cable replaced by single strand
2.5mm TW&E about 40 years ago when such things went metric. If it has PVC insulation it should still be fit for further service. If earlier it could be rubber and likely to need replacing... >In article , .. > Mike P wrote: .. >> The circuit cable is larger. It has 3 coiled earth wires for a start. .. >> I spurred off with a 30amp junction box using 2.5mm. .. >> Why should the cable all be the same size? .. >
.. >It sounds like you've got old cable called 7/0.29.
What you describe, is what I have and it is pvc covered. I have no concern about the cooker feed as it has its own direct supply. To all who feel concerned this is as far as I go with electrics. Though I did move the central heating thermostat to another room.
This saga all arose because wifey got me a junction box from the HB shed, as I did not have the time to go to the local trade leccy. For some inexplicable reason I was reading the instructions that came with it, as I swigged a cup of coffee. It stated that the spur cable should be the same size as the circuit cable .. which made my 6m of 2.5 somewhat redundant ! Hence the questions.
Mike P
Is it?
MBQ
Should be ok for many a year yet, then.
Eh? Is this a red herring? ;-)
All they're saying is that it should have the same current handling capacity as the ring main cable - which means in effect the same type. In your case you're simply using the modern equivalent. The reason for this is it's not the power the socket may take - in your case only small if AV stuff - but to maintain a suitably low earth conductor impedance so the breaker will trip quickly in event of a fault in the wiring to the socket.
What may have confused many was saying you had a triple earth wire. What you really meant was a stranded type which uses three strands twisted together instead of the modern single strand variety.
The message from "Dave Plowman (News)" contains these words:
Hmm.............. While it was general to use 7/.036 for ring main work before metrication, that would have had 7/.029 for the ecc.
If the OP's cable has three strands to the ecc, then it was probably indeed 7/.029 which would have 3/.036 for the ecc. (IEE Regs, 13th Edition)
I've never seen 7/0.36 used for a ring main. Rather overkill and there would be problems wiring it to the sockets where there was a spur.
That could be - it's a bit before my time. The stuff I've seen looked rather like the same size strand used on all conductors.
.. >
.. >I've never seen 7/0.36 used for a ring main. Rather overkill and there .. >would be problems wiring it to the sockets where there was a spur.
Right again .... The terminals were at bursting point .. hence I opted for a junction box.
Mike P
Are the fittings more modern than the wiring? I've a feeling 'metric' ones have smaller holes than the old ones.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.