Conduit Couplers & Expansion Couplers
Couplers join conduit end to end. In the Gulf the expansion coupler matters as much as the straight coupler, because a surface run that cannot move will bow, pull out of its boxes or crack.
Also searched as: conduit coupler, joining coupler, expansion coupler, conduit connector, socket
Straight couplers
A plain socket at each end, solvent cemented to both conduits, giving a rigid watertight joint. Codes run AEMC2 (20mm) through AEMC6 (50mm).
Expansion couplers
A long-entry socket that lets the conduit slide as it expands and contracts. Fit them at a maximum of 6m intervals on surface installations, and reduce that spacing in areas of high ambient temperature or where the temperature swings quickly — which describes most external and plant-room routes in the UAE.
The critical installation detail
Coat the inside of the short side only with solvent cement and push it firmly onto the conduit to the stop. Slide the next length into the long side approximately 50mm and do not glue it. That unglued entry is the whole point of the fitting. Then make sure the conduit is genuinely free to slide in its saddles either side, or the expansion coupler cannot do its job.