Technical Guide
Trenching Depth Guide
Trenching depth isn't a preference — it's set by what the trench needs to do. Here's how depth requirements are usually determined, and how the AFT range compares.
What Sets Trenching Depth?
Depth requirements come from the design behind the job, not from the machine. Drainage depth is set by the fall needed to an outlet. Fibre and utility depth is usually set by a network operator's or local authority's cover requirement. Water pipeline depth accounts for frost cover and vehicle loading where relevant. The trencher needs to reach the depth the design calls for — working backwards from an available machine's maximum depth to decide the design is the wrong order of operations.
Continuously Variable vs. Fixed Depth Control
Some trenchers offer continuously variable, laser-ready depth control, which lets the operator hold a precise, consistent fall over a long run — important for gravity-fed drainage. Others cut to a small number of fixed depth settings, which is often sufficient for fibre, water or utility work where a consistent minimum cover matters more than a precise fall.
Depth vs. Ground Conditions
A machine's maximum depth figure is usually stated for reasonable ground conditions — harder or rockier ground can reduce practical digging speed at depth, even if the machine is mechanically capable of reaching it. This is one of the most common reasons it's worth talking through your exact ground conditions with a TrenchWorks specialist before committing to a machine for a depth-critical job.
Depth Ranges Across the AFT Range
Sorted by maximum digging depth, deepest first — figures are each machine's own specification.
- MH100 — up to 1.8m
- AFT100 — up to 1.6m
- MH45 — up to 1.2m
- AFT45 — up to 1.2m
- Wizz Wheel 75 — 0.75m
- HW60 — up to 0.7m
- AFTraction — 0.6m
- Wizz Wheel 55 — 0.55m
- Sandbander — 0.25m
Common Questions
Trenching Depth Guide: FAQ
What decides how deep a trench needs to be?
The design behind the job, not the machine — drainage depth is set by the fall needed to an outlet, fibre and utility depth by a network operator's or local authority's cover requirement, and water pipeline depth by frost cover and vehicle loading where relevant.
What's the difference between continuously variable and fixed depth control?
Continuously variable, laser-ready depth control lets the operator hold a precise, consistent fall over a long run — important for gravity-fed drainage. Fixed depth settings are often sufficient for fibre, water or utility work where a consistent minimum cover matters more than a precise fall.
Which AFT trencher digs the deepest?
The MH100 excavator-mounted trencher reaches the deepest of the AFT range, with staged depth options up to 1.8m — see the full depth ranges below, sorted deepest first.
Does harder or rockier ground reduce how deep I can trench?
A machine's maximum depth figure is usually stated for reasonable ground conditions — harder or rockier ground can reduce practical digging speed at depth, even where the machine is mechanically capable of reaching it. Talk to TrenchWorks about your exact ground before committing to a machine for a depth-critical job.
Ready to Put a Trencher to Work?
Talk to the TrenchWorks team about your project, or request a quote for the right machine for the job.