What Is a CAT & Genny?
CAT stands for Cable Avoidance Tool, and Genny is short for Signal Generator. Used together, they're the standard equipment for locating buried services before excavation work begins.
The CAT detects signals in two main ways: it can pick up signals that metallic services like live electrical cables emit naturally (power mode), and it can detect radio-frequency signals broadcast by nearby transmitters (radio mode). For services that don't emit a usable signal on their own, such as plastic gas pipes or telecoms cabling, the Genny applies a signal directly onto the line, either by clamping onto it or connecting to an accessible point, which the CAT can then trace.
Used correctly, the two devices together let a competent operator trace the route, and estimate the depth, of buried services before a single spade goes into the ground.
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Why Cable Avoidance Training Matters
Cable and pipe strikes aren't rare, and they aren't minor. Hitting a live electrical cable can cause severe burns, arc flash injuries, or death. Striking a gas main can lead to explosion or fire. Damaging water, sewage or telecoms infrastructure causes serious disruption and can carry significant financial liability for the company responsible.
A CAT and Genny in the wrong hands doesn't prevent any of this. The equipment only works if the operator understands what the signals actually mean, knows the tool's limitations, and follows a proper safe digging process alongside it, including checking utility plans, hand-digging trial holes, and never relying on the tool alone to guarantee a service isn't there. That's what cable avoidance tool training actually teaches: not just which buttons to press, but how to interpret what the CAT and Genny are telling you, and when to trust it.
CAT & Genny training combines classroom theory with hands-on practical use of the equipment. Typical course content includes:
- The different types of buried services and how each one behaves when scanned
- How to carry out pre-use equipment checks
- Using power mode, radio mode and signal (Genny) mode correctly
- Reading and cross-referencing utility plans before digging
- Marking out detected services on site
- Safe digging practices once services have been located, including trial holes and safe clearance distances
- The legal and guidance framework behind safe excavation work
Courses are typically open to anyone involved in excavation work, from operatives and groundworkers through to supervisors and managers overseeing the process, and generally carry no formal entry requirements. Assessment is usually a combination of a knowledge check and a practical demonstration using the equipment.
How CAT & Genny Relates to HSG47
HSG47, Avoiding Danger from Underground Services, is the HSE guidance document that sets out the safe approach to working near buried services, from planning and utility searches through to safe digging and backfilling.
CAT & Genny training is the practical skill that sits underneath that guidance. HSG47 tells you what a safe process for avoiding underground services looks like; CAT & Genny training teaches you how to actually use the detection equipment that's a central part of that process. You can think of it as guidance document versus practical tool use covering the same safe-digging problem from two different angles, and most employers expect their teams to understand both.
Many CAT & Genny courses are delivered as, or alongside, EUSR-accredited excavation training, such as EUSR Category 1 (locating services) and Category 2 (safe digging practices), which formalise the same HSG47-aligned skills into a recognised, time-limited qualification.]
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Whether you're new to groundworks or need to refresh your cable avoidance skills, One Stop Safety Training runs CAT & Genny training that covers the practical detection skills every groundworker needs before breaking ground.
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