Find the Answer
"Check out this splice box we found in a residential attic," says Richard Tanner of Mr. Electric in south Alabama. "Yes, the installer placed PVC couplings over split bolts and filled the void with caulk! Hey, at least they used Romex connectors."
As per 110.14(B), "Conductors shall be spliced or joined with splicing devices identified for the use or by brazing, welding, or soldering with a fusible metal or alloy. Soldered splices shall first be spliced or joined so as to be mechanically and electrically secure without solder and then be soldered. All splices and joints and the free ends of conductors shall be covered with an insulation equivalent to that of the conductors or with an insulating device identified for the purpose. Wire connectors or splicing means installed on conductors for direct burial shall be listed for such use."
It's clear these homemade splice units are not identified or listed for electrical use.