Can You Run a Low-Voltage Wire in a Plumbing Drain Tile?

Insulation Problems

• Where unprotected electrical wiring undergoes flooding, much of the wiring needs replacement before power can safely be restored. Older types of house wiring might include permeable fiber jackets that separate the two conductors. Plastic insulation might suffer damage from fertilizers, caustic chemicals and oils in wastewater flowing through drain tile. Both ends of wiring approved for wet locations must stay dry to ensure safety, according to the Wisconsin Department of Safety and Professional Services. In dry weather, an insulation fault might not cause trouble. In wet weather, an exposed wire can electrify groundwater and deliver a potentially deadly shock.

Wiring Types

• The National Electrical Manufacturers Association does not approve ordinary flexible metal conduit for wiring in wet locations. Liquid-tight flexible metal conduit includes either a waterproof flexible metal sheath or a waterproof synthetic cover. In corrosive environments such as a drainage tile, the conduit must include the synthetic cover. Since running the wiring through a drain tile exposes the wiring to rodents that could damage a plastic sheath, even this waterproofed and armored option does not offer a perfect solution. For the best chance of success, look for a metal-clad cable rated for direct burial or inclusion in masonry or concrete.

Safety Concerns

• A low-voltage line intended to run a pond filter or driveway lighting might not seem like a serious hazard, but low-voltage shocks actually kill people more often than high-voltage shocks. The most dangerous shock comes from current between 100 to 200 milliamps, easily produced by AC house wiring and even by some DC power systems. Alternating current also scrambles electrical signals controlling heartbeat, sending the heart into fatal fibrillation. One death occurred from a shock by only 42 DC volts, according to the Ohio State University Department of Physics. Unmarked, buried power lines also endanger workers who might someday repair problems with the drain system.

Potential Problems

• Even with an armored cable designed for the conditions, placing an electrical wire through a drain tile can cause unwanted problems. Any object in the drain tile encourages other debris to accumulate and contributes to clogs. Drain tiles might eventually need servicing to remove root clogs or other debris. Many of the standard solutions to root clogs, such as drain augers and corrosive chemicals, can damage the cable. Running a cable through a drain tile might seem simpler than digging a trench through a lawn, but burial in the lawn places the cable at less risk and keeps the drain tile clear.