Skill: CAT Cable Avoiding Tool, to Avoid Cables and Pipes
Skill level: 2
Safety
Learning Objective
Learn how to safely locate underground services using a Cable Avoidance Tool (CAT) to prevent accidental damage to electric cables, gas pipes, water mains, or telecoms during excavation work.
1. Overview
Hitting buried services can cause:
Serious injury or death (e.g., electrocution from 230V/11kV cables)
Damage to infrastructure (water leaks, internet or phone outages)
Expensive liability for repairs and claims
Project delays, logistic complications
Loss of trust from customers
✅ Using a CAT before any digging is essential safety practice.
2. Tools & Materials Required
CAT (Cable Avoidance Tool)
Spare batteries for it
Signal generator (Genny), if available
Insulated spade or digging tools
Spray paint or site marking chalk
Notes, app or site log
PPE: gloves, boots, high-vis, hearing protection if needed
3. Before You Start
Ask the customer, land manager for any info regarding underground services.
Be fully aware of the areas you propose to dig and the depths you wish to dig to. It's no good scanning one area and digging another.
Maps of services may be available, find them if possible.
Pay attention to utility entry points such as gas meters, fuse boxes, water taps, or telecom covers. Looking for these clues is equally as important as scanning the ground.
Clear away debris that might obstruct or interfere with scanning. A live extension lead will register as a burried cable.
Be aware of traffic and site safety, you will be looking at the groiund and not your surroundings. Block entrances, cordon off areas as appropriate.
Make sure you know your scanner's settings and operation procedure.
4. Procedure (Main Process)
A. Prepare the Area, as above.
Clear the working zone.
Switch off nearby devices that may cause interference.
Identify possible routes for buried services.
Test scanner on a known live 230v cable.
B. Scan in Multiple Modes
With the scanner almost touching the ground, held vertically, pull the trigger, listen for tones.
Tones indicate presence
Power mode: Detects live electrical cables.
Radio mode: Detects re-radiated signals on metal services.
Genny mode: (with signal generator) gives most accurate readings.
Scan lines horizontally and vertically, and re-scan from different angles.
C. Mark & Communicate
Mark suspected service lines with spray paint or chalk (standard colours).
Record findings/photos in job notes (Clik/app).
Brief your team so everyone knows where services are located.
D. Next steps
Ideally no excavation will take place anywhere underground services are suspected of being.
No signal does not equal no services! Not all service show up, eg plastic water/gas do not show up unless they have a genny connected and have a metal tracer or some metal content.
Depth reading are very rough estimates.
If you have to dig there then follow safe process eg
dig carefully by hand, not machine
use insulated tools
rescan as you dig for more accurate location
never work alone
Learn from what you find. Getting better at scanning involves feeding back to yourself information to better link tones and techniques to actual findings.
If you have to dig a foundation around a cable/pipe then ensure it is physically separated from the concrete by wrapping it in a large duct and or packing so that the pipe and the foundation can move independently from each other in case of ground heave or the foudation being hit by a truck, for example.
Ensure pipes/cables are at sufficient depth to avoid being punctured by drill holes for studs etc...
5. Best Practices
Never skip scanning
Always re-scan after breaks or if unsure.
Treat weak signals as potential services.
Keep batteries charged and test the CAT before each use.
Use insulated tools when digging near suspected lines.
If in doubt, consult site plans or a supervisor.
6. Common Mistakes to Avoid
🚫 Only scanning once — always recheck from multiple angles
🚫 Using a CAT without training or checking battery levels
🚫 Ignoring weak signals that could still indicate live cables
🚫 Assuming service routes without testing each dig point
🚫 Failing to log and share findings with the team
🚫 Forgetting that plastic pipes do not register on the scanner
7. Safety References
Refer to
SSOW-09: Safe Use of Cable Avoidance Tools,
SSOW-01: General Site Safety
SSOW-06: Manual Handling of Tools and Equipment before using a CAT.
Using a CAT and marking the cable
Scanning pattern
Finding a cable, boxed in for protection