My guide to replacing a BT OpenReach Master Socket (NTE5a) … same for Virgin / Talk Talk etc.
Your master socket used to be something like this … and may still do.
C1 = 1.8μF Capacitor
SP1 = Surge Protector
R1 = 470KΩ Out of service resistor
Wiring diagram Master Socket.
There were 3 components, the Ring Capacitor, the Test Resistor and the Surge Protector. It you wanted to add extension sockets you wired them in the back of the socket on the same terminals as BT’s incoming cables.
The introduction of the NTE5 meant only BTs wires are fitted into the back of the socket with a test phone socket on the front – and any extensions are wired into a separate removable front plate/socket – this can be removed should there be an issue with the extension wiring, or to eliminate this from the investigation.
Wiring diagram NTE5A.
Early NTE5’s still had the Surge Protector, but in 2012 these were no longer put in as they can affect ADSL and VDSL speeds. If yours still has it, you can leave or replace the socket. Some people have cut the component out.
There are only 2 components in master sockets now – the Ring Capacitor and the Test Resistor. New sockets (since around 2012) do NOT contain Voltage Surge Protector.
When fitting a new socket:-
- Never strip any cables going into the IDC connectors.
- Always connect to the next available bit of fresh, unused cable.
When placing the wire in the IDC, there is only one correct way. The contact in the IDC connector is off centre, the side that the metal connector is closer to, is the side the wire is cut / ends.
The NTE5’s come with 2 choices of mounting screw. If using a plastic backbox without any metal in the mounting holes, use the self taping screws, otherwise use the machine screw – the machine screws are also for use on the metal back box sunk into wall.
Wiring extension sockets on the faceplate:-
2 = Blue with white rings
3 = Orange with white rings – Don’t connect for best internet speeds.
4 = Not on new sockets
5 = White with blue ring
If your telephone does require a ring capacitor, use a decent microfilter that contains the ring capacitor.