Circular Loop-In Boxes
The loop-in box is the workhorse of a conduit installation — the ceiling point where the lighting circuit loops in and out and the pendant drops. Knockouts on all four sides let the box be used almost anywhere on the run.
Also searched as: loop-in box, circular box, ceiling rose box, conduit box, junction box, 4 way knockout box
Knockout patterns
AE2MRB12 has 4 × ø20mm knockouts; AE3MRB12 has 2 × ø25mm; AE4MBR12 is the mixed pattern with 1 × ø20mm and 1 × ø25mm. Only open the knockouts you need — every unused open entry is a route for dust and for the ingress that eventually shows up as a failed insulation resistance test.
Load and temperature
PVC-U plain bored circular boxes are suitable for suspending loads of up to 3kg centrally at 60°C maximum. Fixing centres are at M4 brass inserts. For heavier luminaires, support the fitting independently from the structure rather than from the box.
Earthing
All boxes have provision for the MET1 brass earth terminal (15 amp). Because PVC-U is an all-insulated system, a separate circuit protective conductor is essential — the containment provides no earth path.