Installing an electrical cable underground to provide power for a 120-volt pond pump will keep the cable out of sight. If done right, this will protect the cable from damage. The electrical cable can connect to a ground fault circuit interrupter outlet by the pump. Careless installations are dangerous to people and pets and may not provide enough power for the pump. When power is not adequate the pump may not run, or worse it may fail prematurely. For distances from power source to pond pump of less than 25 feet, wire size AWG 12 will be adequate.
Dig a trench 24 inches deep, from the power source to the place near the pond where the outlet box will be mounted.
Attach the conduit elbow to a length of conduit that is long enough to reach the desired height at the pond. Set the assembly into the trench, elbow first.
Attach a conduit elbow to a length of conduit that is long enough to provide protection for the cable at the power source end of the trench. Set the assembly into the trench, elbow first.
Lay the cable in the trench.
Slide the cable into each conduit elbow and up through each length of conduit at each end of the trench. Allow enough cable to stick out the top of the conduit at each end to make final connections. Leave some slack in the cable near the point where it enters the elbow.
Hold conduit at each end in an upright position and fill back in the trenches in those locations.
Fill back in the remaining trench.
Check local codes concerning the depth required to bury cable that is not enclosed in conduit. For runs longer than 25 feet, check the Engineering Toolbox in the Resources section of this article to calculate the appropriate size wire to use. In areas with fire ants, moles and animals that burrow, consider enclosing the entire length of cable in conduit.
Many jurisdictions require anyone planning to dig or trench to contact a utility locator service before doing so. Accidentally cutting utility lines while digging can be highly dangerous and expensive. Be sure to use electrical cable rated for underground, direct burial use.