Hello,
Switch sockets such as this normally have a depth listed in the product specifications, in this case it is 33mm. This is how deep the product will protrude back into the wall/box.
As such you can tell how big of a backbox depth you will require by knowing that you need one deeper than the overall depth of the product, which depth is ultimately up to personal choice.
Thank you for using Q&A.
Answered by: WillFarrell
Date published: 2017-11-27