Robotic mower boundary wire repair — diagnose and fix a broken loop

How to know the wire is broken

Robotic mowers all use the same basic principle: a low-voltage current runs around the perimeter loop, and the mower's onboard sensor detects the field. If the current is broken, the field disappears and the mower stops.

Husqvarna Automowers display a 'Loop signal missing' or 'No loop signal' error and refuse to leave the dock. Worx Landroid shows a flashing red base light and 'Wire fault' in the app. Bosch Indego flashes red and red-orange. Flymo EasiLife shows 'Boundary error'. All five mean the same thing: the perimeter wire has been broken or has shorted.

Before assuming a break, restart the dock (unplug for 30 seconds, plug back in) and check the dock's mains power. About 10% of 'wire fault' messages are actually dock or transformer issues, not wire breaks.

Step 1 — Confirm the break before you dig

Disconnect the wire from the dock. Most docks have two terminal screws; loosen both and pull the wire ends out. If your dock has a multimeter port, that's diagnostic gold — but most don't.

Use a multimeter set to 'continuity' or low-resistance. Touch one probe to one wire end and the other to the other wire end. A working loop reads 1–10 ohms (depending on length). A broken loop reads infinite (open circuit). A short reads near 0 ohms.

If you don't have a multimeter, a basic 9V battery and an LED bulb wired in series will tell you the same thing — connect across the wire ends; if the bulb lights, the loop is intact. Multimeters are £15 from Screwfix and worth owning.

Step 2 — Locate the break (the hard part)

There are three methods, in order of accuracy:

Method A — Visual inspection. Walk the entire perimeter slowly. Look for the wire poking up where it shouldn't, or fresh cuts in the grass where mowing or aeration has hit it. About 40% of breaks are visible this way.

Method B — Induction tester. A handheld inductive wire tracer (Klein Tools NCVT-2P or similar, £25) detects the magnetic field around an active wire. With the loop powered up by the dock, walk the perimeter holding the tracer near the wire. Where the field disappears is where the break is. Highly accurate but only works if the dock can provide some signal — a fully broken loop produces no field, so this works best on intermittent breaks.

Method C — Halve the loop. Disconnect both wire ends from the dock. Locate roughly the middle of your perimeter and dig down to find the wire. Cut it. Connect each half to the dock separately and read continuity on the multimeter. The half that's still broken contains the break — repeat the halving process on that half. Crude but effective and requires no special tools.

Tip: 80% of breaks are within 2 metres of where the wire crosses a flowerbed edge, a path, or where you've recently used a fork or aerator. Check those spots first.

Step 3 — Tools you need

Wire stripper (£3 from Screwfix). A sharp Stanley knife works as a backup but is more risky.

Two crimp-style waterproof splice connectors. Husqvarna sells genuine ones at £4 a pair. Generic gel-filled crimp connectors from Toolstation are £2 a pair and work identically. Avoid screw-down connectors — they corrode and fail within a year.

Pliers or crimp tool. A standard combination plier works.

A spare metre of boundary wire of the same gauge as your existing one. Husqvarna and Worx both sell genuine wire (~£8 for 10 metres). Generic 1mm CCA boundary wire from Amazon is half the price and electrically identical.

Optional: a ground stake or two for re-anchoring after the splice.

Step 4 — Splice the wire

Cut both wire ends square. Strip 2cm of insulation from each end with the wire stripper.

Insert each stripped end into one chamber of the gel-filled crimp connector. The connector should have two openings — one for each wire side. Push the wire in until you feel it bottom out.

Crimp firmly with pliers or a crimp tool. The connector should compress around the wires and the gel inside seals against moisture. Tug each wire to confirm the crimp held.

If the break has caused you to lose more than 30cm of wire, splice in a new section. Two crimp connectors and a fresh length of wire — same procedure twice. Don't try to bridge a long gap with screw-down terminals; they fail.

Re-bury the spliced section at least 5cm deep. If the wire was originally above ground (Worx Landroid uses surface-pinned wire on most installs), pin the spliced section back down with the original pegs.

Step 5 — Test and reset

Reconnect both wire ends to the dock terminals. Tighten the screws.

Plug the dock back in. The dock light should go from flashing red to solid green within 30 seconds, indicating the loop is intact.

On the mower, dismiss any error messages and trigger a 'return to dock' or 'start mowing' command via the app or the on-mower controls. The mower should leave the dock, follow the perimeter for a few metres, and confirm 'loop signal' before starting its mow pattern.

If the loop signal is intermittent (mower runs for 5 minutes then errors again), there's a second break or the splice has poor contact. Re-do the splice or use the halve-the-loop method to find the second break.

Brand-specific tips

Husqvarna Automower: the dock has a dedicated 'loop test' button hidden in the engineer menu (long-press the boundary wire indicator). Use it to confirm the loop signal is at full strength after repair. Husqvarna boundary wire is 1.5mm copper-clad aluminium — slightly heavier than generic.

Worx Landroid: the wire is usually surface-pinned, not buried. Breaks are easier to spot but more frequent (lawn mowing cuts the wire constantly). Consider burying after major repairs — a 5cm-deep trench cut with a half-moon edger and the wire dropped in is a 1-hour job.

Bosch Indego: the dock has a clear indicator for short circuits vs open circuits — read it carefully before you dig.

Flymo EasiLife and Yard Force: cheaper boundary wire than Husqvarna, breaks more often. If you've done two repairs in a year, replace the entire wire (£25 for 100m of generic) rather than splicing a third time.

Cost: DIY vs dealer

DIY repair total: £6–£12 (crimp connectors plus a spare metre of wire, optional multimeter at £15 if you don't have one). Time: 30 minutes to 2 hours including hunting for the break.

Dealer call-out: £80–£150 for a Husqvarna technician site visit (most Husqvarna dealers don't quote — call for a price). A Worx engineer site visit is £75–£120. Most dealers do this work; few advertise it.

Replacement of the entire wire: £25 in materials for 100m of generic boundary wire, plus a couple of hours of work. Worth it if you're getting recurring breaks or the wire is over 5 years old.

Prevention

Bury the wire 5–10cm deep, not just pinned to the surface. Worx Landroid's surface-pinned default is convenient but causes 80% of break complaints. Burying takes a half-day once and then the wire lasts 10+ years.

Mark the wire path. Two or three small garden markers around the perimeter remind you where not to fork or aerate. Photograph the layout from a window upstairs as a reference.

Keep the dock undercover. The dock is the actual brain of the loop signal — water ingress on the dock terminals causes more 'wire fault' messages than actual wire faults. A small canopy or birdhouse-style cover extends dock life dramatically.