I had to move some of my irrigation pipes a few feet to make room for a deck expansion. There were wires routed along with the PVC pipes that need to be moved also. The wires are not long enough to reach so I need to splice in some new wiring. I plan to use the wire nuts for direct burial. Problem is, I can't find the underground wire that I need. I've tried big box stores, several electrical supply houses, and the irrigation supply place.

The gap in wiring is about 18". The re-routed wiring will be located under our raised deck when the project is finished. Are there any other options, such as using 2 outdoor boxes with regular wiring encased in a pipe between the 2 boxes? I'm ok with leaving something above ground for this short piece that will be under the deck and can be covered with mulch. All creative ideas welcome. Thanks.