Through Boxes & Terminal Boxes
The two simplest boxes on the run. A terminal box closes the end of a run at an accessory; a through box provides an inspection and pull point part-way along a straight length.
Also searched as: through box, straight box, terminal box, one way box, two way box, inspection box, stop end box
Terminal 1-way
A single entry, used where the conduit run stops — at a switch position, a socket outlet or an isolator. Codes AE2MRB2 (20mm) and AE3MRB2 (25mm).
Through 2-way
Two entries in line, giving a draw-in point on a straight run. On any long horizontal or vertical route, planning through boxes at sensible intervals is what makes the cable pull achievable — retro-fitting an access point into a cast-in run is not an option. Codes AE2MRB3 (20mm) and AE3MRB3 (25mm).
Fixing and finishing
All boxes have threaded brass inserts for the lid screws, so lids can be removed and refitted repeatedly without stripping. Fit the correct lid — AEMCL1 at 65mm diameter, or the MCL2 overlapping lid at 85mm where the box has been set slightly proud or the plaster line is imperfect.