Question regarding master and slave telephone sockets

30 Oct 2007
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United Kingdom
Hi guys, I have a telewest phone line coming into my building. I have a master phone socket where both slots 2 and 5 are occupied by white/blue and blue cores from the main line and also the alarm wire going to the alarm control box.

So basically each of the two slots has two core kroned in. Now the problem is that I have slave telephone socket which was to connect from the master socket also i.e. resulting in 3 cores in each of the two slots however the third core from the slave socket wont krone in.

Now the question is, with the slots 2 and 5 being occupied by the main wire and alarm wire, how can i connect the slave socket to the master. Can I use any of the other slots.

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Is your master socket an NTE5?


If so, the incoming line should be in the hidden screw terminals behind the main faceplate. Your extensions should be wired to the Krone terminals on the lower removeable part.
MrHumbug, I was actually provided such a socket but I wanted everything MK to follow the consistant design and look of the building. Sadly the MK one doesnt look anything better than its slave version other than some yellow capacitor thing
You should put it back. I don't know what Telewast (now Virgin, of course) is like about their socket, but BT want you to use theirs - and it is their socket, not yours.

As far as connecting mutiple cables together after the telco socket, you could use one of these:

You can get two wires in a Krone terminal so the junction box would allow you to connect four cables.

The other thing you seem to be doing is wiring your extensions directly to the incoming line, not to the user side of your master socket. That will cause you problems with getting you extensions to ring. There may be other problems that a telephone engineer could explain to you as well.


which explains about master and secondary telephone sockets and phoen wiring.
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MrHumbug, im not really too clued up on all this to be honest but when Virgin sent their guys out for the install, they were more than happy for me to put my own socket on and even showed me what to do. Strange though as they told me to make sure the solid blue is in 2 and white/blue in 5 for all the cables.

Likewise I was going by what they were telling me.

Now, im assuming they were giving me wrong information and likewise lets say I put the following to you, how would you tackle the situation;

I want the main line coming into the master socket for a telephone located in front of the socket. I want the alarm wire going into the same socket. And I want a slave socket sunning off this socket for another location in the building for another phone. Using only a MK salve and MK master sockets what would you do i.e. what would you krone into what

so far I have the blue and blue white of the main and alarm wires kroned into 2 and 5 respectively. I have the orange wires bare i.e. just loose. The slave socket is again basically a sitting duck doing nothing as I dont know which coloured cores need to go in which slots considering the other end isnt kroning in properly due to 2 cores occupying the slots already and furthermore, you mentioning the last paragraph.

How would I do it?

I'd keep the NTE5 where it's supposed to be and wire from the removable faceplate on that. Fewer problems if something goes wrong in the future.

I've no experience of dealing with Virgin when a fault arises, but BT always wants you to disconnect your stuff to prove it's a line fault. The NTE5 is perfect for that.
Sorry for a late follow up Mr Humbug,

Regarding this issue, lets say i was to stick with the MK socket, would this work if i was to krone the main line cores into 2 and 5 but not snipping off the excess. Then making this excess bare and connecting the cores to those from the cable going to the slave socket. Very unorthodox im assuming but would it work?

If you insist on removing the NTE5 then join the wires in a junction box. Twisting bare wires together and covering with sellotape is asking for trouble later on.

(I know you didn't mention sellotape, but that's where it's going... )

All of your sockets will need to be masters.

I only know of one type of NTE5, but there are some different faceplates you can get for the lower half.
All of your sockets will need to be masters.

Not a good idea if the local exchange has an automatic line tester that can detect multiple masters ( some can ) and BT is having a bit of a purge.

You really should leave the incoming pair connected to the BACK of the NTE 5 and then connect your internal wiring to the REMOVABLE fromt plate of the NTE 5.
Not all sockets would need to be a master. Just one, as long as the 2/5/3 are paralleled.

Having two many masters can cause the line to show as excessively long on a line test.
If you can get hold of them use some jelly crimps, krone a pair off the socket then use jelly crimps to split one to the alarm and the other to your slave socket.
The best way to do it is to design your wiring layout so there's no more than two cables at any point. So you could:-

a) run your new socket from your existing extension socket

b) remove the existing extension wiring, and re-run your existing socket from your new socket

c) remove the alarm connection, and re-run it to your new socket.

There is no need for any more than one master socket on correctly designed wiring

Multiple 'star' connections from a single point can adversley affect ADSL speeds if you use broadband.

Removing the NTE or making connections to the line side of the NTE can leave you liable to charges for a maintenance callout if an engineer visits, even if the visit wasn't at your request.
I only know of one type of NTE5, but there are some different faceplates you can get for the lower half.

There are two manufacturers-Pressac and Austin Taylor. AFAIK the Pressac version is the only one to have the new bell wire filter/inductor.

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