Bosch Professional GMS 120 Wall Scanner and Cable Detector

Bosch Professional GMS 120 Wall Scanner and Cable Detector

By Bosch · Model: GMS 120 · Electrical & Lighting

Professional 3-in-1 wall scanner detecting live cables, metal pipes and wooden studs up to 120mm deep.

  • Three detection modes: drywall, metal, and live cable
  • 120mm max detection depth for ferrous metals
  • 50mm max detection depth for live cables
  • Centre-finding function pinpoints the exact position of objects
  • Illuminated ring signals detection results with traffic light colours
  • One-handed operation with clear LCD display
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Overview

The Bosch GMS 120 is the go-to wall scanner for electricians, plumbers and general builders who need to know what is behind a wall before drilling. Its three detection modes cover live cables, metal pipes and wooden studs, while the illuminated ring provides instant traffic-light feedback — green for safe, red for danger.

In-Depth Look

The Bosch GMS 120 is one of those tools that every trade van should carry. A few seconds of scanning before drilling can prevent cutting through a mains cable, puncturing a water pipe, or missing a stud entirely.

Three Modes

The drywall mode detects wooden studs and joists behind plasterboard. The metal mode picks up ferrous and non-ferrous metals — copper pipes, steel beams, rebar. The live cable mode detects energised wiring. Switching between modes is a single button press.

Traffic Light Feedback

The illuminated ring around the display changes colour as you scan: green when the area is clear, yellow when approaching an object, and red when directly over it. This is far more intuitive than numerical displays, especially when working overhead or in dim conditions.

Verdict

The Bosch GMS 120 is the professional wall scanner that trades across all disciplines rely on. Its combination of three detection modes, centre-finding accuracy, and intuitive traffic light display makes it an essential safety tool for anyone who drills into walls.

Specifications
Detection Depth (Ferrous Metal)120mm
Detection Depth (Non-Ferrous Metal)80mm
Detection Depth (Live Cable)50mm
Detection Depth (Wood)38mm
ModesDrywall, Metal, Live Cable
Power1x 9V battery
Weight270g

Who It's For

  • Electricians checking for existing cables before chasing walls
  • Plumbers and heating engineers locating pipes before drilling
  • Kitchen and bathroom fitters needing to fix into walls safely

Pros & Cons

Pros

  • Three detection modes cover cables, metal and wood in one tool
  • Centre-finding function gives precise drilling positions
  • Traffic light ring is intuitive and visible in low light
  • Professional Bosch quality with reliable calibration

Cons

  • Requires careful calibration on each new wall surface
  • 50mm cable detection depth may miss deeply buried cables
  • 9V battery life is limited with heavy use
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