Which practice best minimizes the risk of stray voltage affecting irrigation valves?

• A. Use only one cable for both power and control
• B. Run control wiring in a separate trench or conduit away from power wiring
• C. Bury all conductors at the same depth
• D. Use metal conduit for all wiring

Answer: (B)

The key idea is electrical separation: keep the low-voltage control wiring physically apart from the high-voltage power wiring. When control and power runs share the same trench or conduit, stray voltage can couple from the power circuit into the control circuit through ground paths or capacitive/inductive coupling. That energy can energize valve solenoids, cause nuisance operation, or create safety risks. Running the control wiring in a separate trench or conduit away from power wiring minimizes these coupling paths, helping the control circuit stay isolated from faults or leakage on the power side and making valve operation more reliable and safe.

Sharing a trench or using a single cable for both circuits allows stray voltage to move between them, increasing the chance of unintended valve energization. Merely burying all conductors at the same depth doesn’t address the electrical interaction between circuits. While metal conduit offers protection, it doesn’t fully prevent coupling or fault energy from affecting the control circuit if power wiring has issues. Separation provides the strongest safeguard against stray voltage affecting irrigation valves.