BT Master Telephone Socket - Black Nickel Screwless

The Knightsbridge BT master telephone socket provides the primary connection point for incoming landline telephone service, housing a surge arrestor and R/C filter that protect downstream equipment and allow service provider testing without disconnecting devices. The screwless black nickel faceplate measures 87.5mm square and uses a clip-on cover plate over a separate metal sub-frame, eliminating visible fixings on the wall.

Designed for residential and light commercial installation where telephone service terminates at a wall-mounted connection point, the socket accepts standard BT431A plugs and provides screw terminals for incoming line connection. The built-in surge arrestor protects against voltage spikes from lightning strikes and network faults, while the R/C filter allows engineers to isolate the internal wiring for line testing. The master socket designation means it sits at the demarcation point between service provider and customer wiring.

The black nickel finish is created by applying a dark nickel plating to 201 stainless steel, producing a charcoal-toned metallic surface that pairs with contemporary and industrial interiors. The screwless design uses a low-profile cover plate with a built-in gasket that sits flush to the wall with 4.3mm projection. The socket requires a standard 25mm minimum back box depth and carries BS 5733 certification for UK telephone service connection.

Product Specification Sheet

What is a master telephone socket?

The master socket is the primary connection point where the telephone service provider's external line enters the property. It contains a surge arrestor and filter that protect downstream equipment and allow engineers to test the incoming line by isolating customer wiring. All other telephone extension sockets in the property connect to this master socket.

What back box depth is required?

A 25mm minimum back box depth is needed for installation. The screwless cover plate adds 4.3mm projection from the wall once fitted.

Is the screwless plate removable for redecorating?

Yes. The cover plate clips onto a separate metal sub-frame fixed to the back box. The cover can be removed for painting around the socket and re-clipped without disturbing the wiring.

What other finishes are available?

Knightsbridge produces this master socket in a range of finishes including polished chrome, brushed chrome, polished brass, antique brass, matt black and white. Use the search function or filters to find other variants in stock at Niori.