You need to contact the manufacturer. Most claim that the reinforcing in the LBs creates a strength comparable to Sch. 80 conduit. In my experience I have seen Sch. 40 conduit fail but have yet to see an LB broken. Be carfull about using a metal LB if it is connected to PVC at both ends and has service conductors, because you now have to bond the LB. Alan--Inspector.
