Extending PVC Conduit

I need to move the control box for my well pump several inches out from the wall where it is mounted. I don't want to un-wire it. There is enough slack to do this. However, the pvc conduit from the wall to the right angle hub (with the oblong cover - i think they are called LB Style) will be too short. Anyone know a way I can get a coupling or a small piece of conduit around the wires? Code implications?

Extending PVC Conduit