What are the standard dimensions of a UK single and a UK double pattress box?

Question

I know the depth varies and I think the standard depth for both is 25mil. I think a single is 86mil squared and that a double is 147 x 86. anyone know for sure? All ye electricians out there?

Answer 1

And there is also a 'twin' which is two singles side by side.

The box can go back as far as you need, but typically they are 25, 50, and 75mm deep. Generally, you'll need MORE space in the box with more wires or the thicker wires. Actually, the limiting factor for the depth is the length of the screws to the face plate!!!

Answer 2

Well done! ( did you measure all of your sockets & switches in your house ? ) No there is no standard depth it depends on what you are fitting to it.  But why do you ask ?