The dimensions are:
Length x 89mm
Width x 35mm
Depth x 30mm
NOTE: Total depth is 30mm into the wall and face plate is 1.6mm


Please go to the website via the following links below and check under the Documentation Tab for more information.
Australia - https://www.clipsal.com/products/detail?CatNo=B31A&itemno=B31A-WE&backto=/search?q=B31A&tab-document-1=0
https://www.clipsal.com/products/detail?CatNo=BB31A&itemno=BB31A-WE&backto=/search?q=BB31A&tab-document-1=0
New Zealand - https://www.pdl.co.nz/products/detail?CatNo=B31A&itemno=B31A-WE&backto=/search?q=B31A&tab-document-1=0
https://www.pdl.co.nz/products/detail?CatNo=BB31A&itemno=BB31A-BK&backto=/search?q&tab-document-1=0