Electromagnetic line locating. How buried lines are actually found.

It's the method of finding buried conductive utilities by electromagnetic signal: a transmitter puts a known frequency on a metal pipe, cable, or tracer wire (or the line already carries power or radio energy), and a receiver follows that signal from the surface to trace and mark the line's route and estimate its depth. It's the core technique of private utility locating and the conductive half of a dual-method (EM + GPR) locate.

Active locating applies a chosen frequency to a specific line — by direct connection, clamp, or induction — so you trace that one identified line precisely. Passive locating detects signals already present (live power at 50/60 Hz, or re-radiated radio) to sweep an area for conductors without applying anything, but it can't tell you which line is which. Professionals use passive to discover and active to identify and trace — they're complementary, not alternatives.

Three ways to get a signal onto a line. Direct connection clips the transmitter to a conductor at an access point for the strongest, cleanest, longest trace — the default when a connection exists. A signal clamp wraps around a pipe or live cable to induce the signal without breaking the circuit — essential on energised power. Induction broadcasts the signal into the ground from the surface where no access point exists at all — versatile but less precise, since it can energise several nearby lines. Method selection is the locator's craft.

Not on its own — bare plastic carries no signal, so it's invisible to every EM mode. Plastic mains are found three other ways: by their tracer wire if one was installed (then it traces like any conductor), by pushing a sonde through the line, or by GPR imaging the pipe itself where soil allows. This is exactly why a real locate is dual-method: EM for the conductive lines, GPR and sonde for the non-conductive ones. An EM-only 'all clear' is never a complete clear.

From the signal's characteristics — its strength and field geometry let the receiver estimate burial depth at a point on a clean active trace of a reasonably isolated line. It's an estimate, not a survey measurement: accuracy degrades where lines run close together or the signal is distorted. For decisions that depend on exact depth (a tight crossing, a bore), the estimate is confirmed by GPR and ultimately verified by hand-exposure or vacuum potholing. We state depths as estimates and pothole the critical ones.

Because each finds what the other can't. EM traces conductive lines precisely and tells you which is which, but is blind to non-conductive plastic and clay. GPR images the subsurface including those non-conductive lines, but can't label conductive lines the way an EM trace can. Run together, EM identifies and traces the metal and tracer-wired lines while GPR catches the plastic, the clay, the concrete duct, and the unknowns — and confirms the EM work. Dual-method is the standard a defensible locate is measured against.

Only for the public half. BC One Call notifies member utilities to mark their public lines to the property line — it does not locate the private services beyond it: your water service, irrigation, private power, gas to outbuildings, septic. Those private lines are where most digs actually strike, and they're the digging party's responsibility. The right approach is both: BC One Call for the public locates, a private EM + GPR locate for everything on your side of the line.

Yes — the inductive signal clamp is built for it: it couples a locating frequency onto an energised cable without any electrical contact and without interrupting supply. It's the standard professional method for tracing live power and is far more reliable than trying to follow the cable passively through a corridor of other conductors. A passive power sweep flags what's energised first; the clamp then traces the specific feed.

A sonde is a small self-powered transmitter pushed through a non-metallic pipe — on a rod or a CCTV camera head — that broadcasts a locating signal from wherever it sits, so the receiver can pinpoint it from the surface. It's how plastic and clay drains, which carry no signal of their own, get traced; advancing the sonde and re-locating maps the whole line. Paired with a drain camera, it also marks the exact ground position of a blockage or defect the camera finds.

Tracer wire is a conductor buried alongside a non-metallic main at installation specifically so the otherwise-invisible line can be located electromagnetically later. On new plastic water, gas, or irrigation mains, install it — unconditionally: the cost at install is trivial against an unlocatable buried main every future dig has to guess around. Detail it with access points at valves or markers and continuity-test it before backfill, and the line stays as locatable as metal for decades.

Yes — EM fault-finding pinpoints where a conductor has failed (an open break, a short, or a sheath fault leaking to ground), not just that it has, so the repair is one targeted dig instead of a trenched run. We characterise the fault type first (each needs a different technique), trace to the fault, mark it with depth, and verify continuity after the repair. It's how a faulted tracer wire gets fixed instead of abandoned.

No honest locator promises that — abandoned lines, unmarked private installs, and the limits of every instrument in difficult ground all exist. What a proper dual-method survey does is reduce the risk as far as detection technology allows, and the responsible final step before machinery is hand-exposure or vacuum potholing at the critical crossings to physically confirm the line. We locate thoroughly, document it, and are candid that potholing is the last word on safety.

Province-wide pricing with no regional premium. A focused clearance — a dig area, a fence line — starts in the low-to-mid hundreds; full-site location, depth mapping, as-builts, and SUE-grade data are quoted by scope. Against the cost of a single struck line, the locate is the cheapest line on the job. The free phone consult gives a firm number in about five minutes: 604-239-9934.