Containment guide

Wireless dog fences and metal: why boundaries shrink

Radio and metal don't mix.

By SnoutSmart Editorial · Updated October 2026

The short answer

A wireless fence's transmitter broadcasts a circle, and metal blocks and reflects that signal. PetSafe advises keeping its transmitter at least 3 ft from metal and notes metal roofs and RVs can shrink the boundary. Place the transmitter centrally, high, away from appliances and metal siding.

What interferes

  • Metal roofs and siding.
  • Large appliances such as refrigerators.
  • Vehicles and RVs.
  • Thick masonry walls.

Placement tips

  • Keep the transmitter at least 3 ft from metal (PetSafe).
  • Place it near the center of the area you want.
  • Raise it off the floor.
  • Walk the boundary with the collar after any move.

Systems we cover

PetSafe Wireless Containment covers a circle up to 180 ft across; Stay & Play Compact up to 3/4 acre.

SafetyNo electronic fence is a physical barrier. Never rely on one alone near a busy road.

Products mentioned

Questions readers ask

Can I use a wireless fence in an RV?
Metal RVs can shrink the boundary a lot; check before relying on it.
Why does the boundary move?
Interference and signal reflections change the circle's edge.