Underground electrical terminal boxes and cabling problem

[postandrail]

I have a need to connect a 10mm OD flexible PVC cable to a SWA cable.

I have nowhere to fit a terminal box above ground, is it feasible to use an IP67 Plastic JB underground with a IP66 Nylon Cable Gland (for the PVC cable) and a CW20S 3 part external gland (for the SWA).

Or what other alternatives do I have.

[Andrew Gabriel]

I would use a resin filled junction box. A conduit box underground is eventually going to get moisture in it pretty much whatever you do. It should have a drain hole, but underground, that will double up as a fill hole ;-) Leave some slack cable around the JB so if the join does fail, there's some spare cable for making off new ends.