Drilling blind into a wall is one of those gambles that goes fine ninety-nine times and then drills straight through a buried live cable or a copper pipe on the hundredth. At best you trip the board and feel a fool; at worst you are looking at a shock, a flood, or a very awkward conversation with the customer. A decent cable detector costs less than one call-out to put right a drilled pipe, and it lives in the top of the toolbox for a reason.

This is a straight, practical guide to the cable detectors and wall scanners worth buying in the UK right now. We cover cheap one-button units for the occasional fixing, proper multi-mode wall scanners for electricians and kitchen fitters, and the dedicated cable tracers a sparks uses to find a specific circuit behind the plaster. No jargon, just what actually matters before you pull the trigger on a drill.

Our quick verdict

For most tradespeople, the Bosch GMS 120 Professional is the one to buy. At around £100 it detects live cables, ferrous and non-ferrous metal, and timber studs with a proper depth readout and a clear centre-finder, and it is built to survive life in a tool bag. It is the sensible default for electricians, kitchen and bathroom fitters, joiners and anyone drilling into other people’s walls for a living.

If you only need to check a wall before the odd fixing, do not overspend — the Bosch Truvo one-button detector at around £40, or the UniversalDetect at around £55, will keep you out of trouble on domestic work. And if you are a sparks who needs to trace a specific cable or find which breaker feeds a socket, that is a different tool altogether: a dedicated cable tracer like the Fluke 2042, not a wall scanner.

At a glance: the cable detectors compared

Prices are inclusive of VAT and reflect typical UK retail at the time of writing from Screwfix, Toolstation and Amazon UK. Detection depths are the manufacturer’s figures for ideal conditions — treat them as a best case, not a promise.

Detector	Type	Detects	Approx price	Best for
Bosch GMS 120 Pro	Multi-mode wall scanner	Live cable, metal, wood	£95–£115	All-round trade use
Bosch UniversalDetect	Wall scanner	Live cable, metal, wood	£50–£60	Light trade & DIY
Bosch Truvo	One-button detector	Live cable, metal	£35–£45	Quick pre-drill checks
Fluke 2042	Cable tracer (Tx/Rx)	Cable routes, breakers, faults	£350–£450	Electricians tracing circuits
Bosch D-tect 200 C	Radar wall scanner	Cable, pipe, metal, cavities	£450–£550	Structural & pre-chase surveys

The best cable detectors for UK trade in 2026

Bosch GMS 120 Professional — best all-round wall scanner

The GMS 120 is the detector you see clipped to more tool bags than any other, and for good reason. It runs three modes — a universal mode that flags live cables, ferrous and non-ferrous metal and timber studs, plus dedicated metal and drywall modes for pinning down exactly what is behind the plaster. It auto-calibrates when you switch on, gives you a depth readout up to 120mm for metal, and the three-colour LED ring plus centre-finder scale make it quick to mark the exact edge of a stud or the run of a cable. It is not radar and it will occasionally get confused by foil-backed plasterboard or dense masonry, but for everyday drilling and chasing it is accurate, fast and tough. At around £95 to £115 it is the value pick for anyone doing this for a living.

Bosch UniversalDetect — best value for light trade and DIY

The UniversalDetect is the sensible step up from a bargain-bin stud finder without paying professional money. It flags wooden studs, live cables and metal at roughly 25mm, 50mm and 100mm respectively, with a simple LED display that turns red when it finds something and a signal-strength readout so you can centre on it. It is a green-line DIY tool rather than a site-hardened professional one, so it will not take the same abuse as a GMS 120, but for a kitchen fitter putting up the odd wall unit or a landlord doing their own maintenance it is more than enough. Around £50 to £60.

Bosch Truvo — best budget one-button detector

The Truvo strips detection back to a single button and a ring of LEDs — no modes, no menus, no depth figures. Press and sweep, and it lights up over live cables and metal so you know where not to drill. That is genuinely all a lot of people need before hanging a shelf or a TV bracket. It will not tell you how deep something is or distinguish a pipe from a cable, so it is a keep-you-safe tool rather than a diagnostic one, but at around £35 to £45 it is cheap insurance to keep in the van as a loaner or a backup. Buy one for the apprentice.

Fluke 2042 — best cable tracer for electricians

This is the tool people mean when they say they need to ‘trace a cable’, and it is a completely different job to wall scanning. The 2042 is a two-part transmitter-and-receiver kit: you clip or plug the transmitter onto a de-energised cable, then sweep the receiver along the wall or floor to follow the route, find which breaker feeds a circuit, or locate a break or short. It works on live and dead cables and traces through walls, screed and underground runs. It is overkill for putting up a shelf and it will not tell you where a random pipe is, but for a working electrician chasing faults or identifying circuits in an unmarked board it earns its keep. Around £350 to £450 for the transmitter-and-receiver set.

Bosch D-tect 200 C — best premium radar scanner

If you are drilling or coring into structural concrete, or you need to know what is buried before you chase out a wall on a commercial fit-out, a radar scanner is the honest answer. The D-tect 200 C uses radar rather than simple induction, so it maps live and dead cables, plastic and metal pipes, timber and even cavities to real depth, with a proper display that shows what it has found. It is heavy, it needs a bit of technique to read well, and at £450 to £550 it is a serious purchase — but for the tradespeople who need it, nothing cheaper does the same job with the same confidence.

Wall scanner or cable tracer — which do you actually need?

These two tools get lumped together as ‘cable detectors’ and they answer completely different questions. A wall scanner like the GMS 120 tells you whether there is anything behind the plaster right here, before you drill. A cable tracer like the Fluke 2042 tells you where one specific cable goes, or which breaker controls it. Buying the wrong one is the most common mistake people make.

If your worry is drilling into a live cable or a pipe when you hang, fix or chase, you want a wall scanner and the GMS 120 covers almost everyone. If you are a sparks trying to identify circuits, follow a route or find a fault, you want a tracer and a wall scanner will not help you at all. Plenty of electricians end up owning both, because they solve genuinely separate problems.

Buyer’s guide: what to look for

Detection modes

The cheapest detectors only flag live AC and metal. Better ones add a wood or stud mode and separate ferrous from non-ferrous metal, so you can tell a joist from a pipe from a cable. If you drill into varied walls all day, multi-mode detection saves you second-guessing what the beep actually means.

Depth readout

A simple detector tells you something is there; a better one tells you how deep. A depth figure matters when you are choosing fixing length or deciding whether a shallow cable is in the danger zone for the screw you are about to drive. Remember the quoted depths are best-case — knock a margin off for real walls.

Live cable detection

Induction detectors only see a live cable when it is actually carrying current, so a switched-off circuit can read as clear. That is exactly why you still isolate, and why a radar scanner or a proper tracer is safer around dead cables. Never treat a ‘nothing here’ reading as a guarantee on a circuit you have switched off.

Build and calibration

A professional detector auto-calibrates on start-up and shrugs off being dropped in a bag of tools; a DIY one needs careful handling and a steady sweep to read right. If it is going on site every day, spend the extra for the tougher unit — a detector that reads inconsistently is worse than none, because it breeds false confidence.

FAQs

Can a cable detector find cables through any wall?

No. Induction detectors read live cables and metal near the surface reliably in plasterboard and standard plaster, but foil-backed board, dense masonry and metal lath can block or confuse them. Radar scanners cope with far more, which is part of why they cost more. Always sweep slowly and cross-check from two directions.

Will it detect a cable that is switched off?

Not reliably, if it is a basic live-cable detector — those only sense current flow. Metal-mode detection will still pick up the copper conductor, and radar scanners see the cable itself regardless, but this is exactly why you isolate and prove dead before drilling near anything you cannot see.

Do I need a stud finder as well?

Usually not. Any of the multi-mode wall scanners here find timber studs as well as cables and metal, so a separate stud finder is redundant. A dedicated stud finder only makes sense if all you ever do is hang things on timber-framed walls and you want the cheapest possible tool.

What is the difference between a cable detector and a CAT and Genny?

A wall detector is for the surface of a building — finding cables and pipes before you drill indoors. A CAT and Genny (cable avoidance tool) is a groundworks tool for locating buried services before you dig outside. They look related but are built for completely different jobs, so do not buy one expecting to do the other.

The bottom line

For the widest range of tradespeople, buy a Bosch GMS 120 Professional and keep it in the top of the bag — it tells you what is behind the plaster before you drill, and that is the question most people need answered. Keep a cheap Truvo as a loaner and a backup. If you are a working electrician who needs to trace circuits or chase faults, that is a Fluke 2042, not a wall scanner — a different tool for a different job. And if you are coring structure or surveying before you chase, the D-tect 200 C is the radar-grade answer worth the money.