I have two lamposts on either side of my front patio. They are mounted to the concrete, and the wiring is buried. Occasionally, usually when it's wet outside, turning on the lights will trip the circuit breaker. Sometimes this happens immediately after turning on, sometimes it takes a while. I'm assuming there's an issue with the wiring in the ground, and it's causing a short. I'm wondering how hard of a fix this is, and how much it's likely to cost to fix. My house is on a slab, if that makes a difference in how the wiring is run.